Obturation material delivery device

ABSTRACT

A delivery device for delivering filling material into the canal during a root canal procedure includes a shaft having a bed portion at a distal end thereof, and a biocompatible filler material mounted to the bed portion. The filler material includes an upper surface, a side surface, and a distal end. The delivery device bed portion has a greater thermal conductivity than the filler material; and the bed portion of the shaft wraps at least partially around the filler material and contacts the filler material substantially along the length of the filler material from the upper end of the filler material to at, or proximate, the distal end of the filler material. This delivery device allows for better control of temperature delivery and position of the filling material and allows for a more thorough and precise heating of the filler material in vivo.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International App. No.PCT/US2012/033237, having an international filing date of Apr. 12, 2012,and which claims priority to U.S. App. No. 61/476,100 filed Apr. 15,2011 and U.S. App. No. 61/620,229 filed Apr. 4, 2012, all of which areentitled “Endodontic Obturation System” and all of which areincorporated herein by reference. In addition, this application isrelated to the following co-owned applications which are filedconcurrently herewith: application Ser. No. 13/714,988, entitledEndodontic Plugger, application Ser. No. 13/715,045, entitled “HolderFor Obturation Material Delivery Device”, and application Ser. No.13/715,068, entitled “Endodontic Obturation System And Method”, all ofwhich are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND

1. Field

This application relates generally to obturation systems and methods foruse during an endodontic (root canal) procedure to, for example,three-dimensionally seal and fill at least the apical end of a rootcanal after the root canal has been shaped, cleaned/disinfected, anddried.

2. Description of Related Art

A tooth comprises a crown, which is visible above the gum line, and oneor more roots, which extend from the bottom of the crown. The toothroots, and hence the tooth, are secured into bone by periodontalligaments. Each root includes a canal that is filled with a livingtissue, referred to as pulp. For a variety of reasons, the pulp canbecome diseased or otherwise become infected. Such infections adverselyaffect the tooth and its supporting structures. When the pulp in theroot canals becomes infected, the tooth can be pulled (i.e., extracted).

Clinically, as an alternative to extraction, root canal treatment can beperformed. Root canal treatment is directed toward preparing the rootcanal to eliminate the pulpal tissue, bacteria when present, and relatedirritants from the root canal system.

SUMMARY

Several embodiments of the invention are directed to facilitatingsuccessful outcomes for root canal procedures. Following root canalpreparation and disinfection procedures, an objective for successfuloutcomes is for the root canal system to be three-dimensionally filledwith an inert, biocompatible, dimensionally stable, obturation(filling/sealing) material, such as a gutta-percha, in an effort toeliminate space for bacteria to colonize. If bacteria are given space toform a colony in the root canal, the bacteria, their noxious by-productsand toxins, and corresponding infection, can exit the root canal throughthe apex and other communications from the canal and spread into thesurrounding tissues. Several embodiments of the invention areparticularly advantageous because the obturation procedures will fillnot just the main canal, but all or substantially all of the anatomy ofthe root canal system, including any fins, webs, cul-de-sacs and lateralcanals present in the root canal system, and seal all the portals ofexit between the root canal system and the tooth's attachment apparatus.

Briefly stated, the obturation system shown in the drawings anddescribed below was designed for accurate sealing of at least the apicalend of the root canal with a filler material (such as gutta-percha). Thesystem can be configured to provide for near automatic sealing of theroot canal. This is facilitated by, in some embodiments, a feedbacksystem that includes location of the filler material's placement, directheat delivery to the filler material for controlled transfer of heat andsimultaneous three-dimensional forces of compaction. In one embodiment,the obturation system comprises a delivery device that at leastpartially wraps the filler material and extends to the tip (or withabout 2 mm therefrom) of the filler material, a base unit, a holderwhich removably receives the delivery device and which is incommunication with the base unit, a plugger, also with connection to thebase unit, and a lip clip. As will become apparent, the disclosedplugger can be independent of the system or incorporated in the system.The plugger, or portions thereof, may be made of one or more thefollowing materials: Nitinol (NiTi), memory wire or other materialswhich can withstand the forces to which the plugger will be exposedduring use.

Briefly stated, according to one embodiment of the obturation system, adelivery device (e.g., a filler material delivery device) is providedfor delivering a plug of filler material into a root canal. As describedbelow, in one embodiment of the obturation system, the delivery deviceis operable to confirm that the plug of filler material is in positionat the apex or working end of the prepared canal, and then to regulatethe direct delivery of heat to the plug of filler material in the canal.The system then allows for a new three-dimensional form of molding ofthe filler material in the canal while the filler material is beingheated, thus assuring that the filler material is at a moldabletemperature while it is simultaneously molded into the root canal.Finally, the system will remove the delivery device while molding iscompleted, leaving only the filler material in the root canal.

In one embodiment, the delivery device comprises an elongate shaftextending from an upper gripping or connection portion. All or a portionof the delivery device comprises a material that has a thermalconductivity in the range of about 100 w/mK to about 2500 w/mK, e.g.,between about 200-500 w/mK. In one embodiment, at least a portion of thedelivery device comprises a material having a thermal conductivitysufficient to generate a temperature gradient of less than 20° C. (e.g.,less than 15° C., less than 10° C., less than 5° C., etc.) from theproximal end of the filler material to the distal end of the fillermaterial or a distance of about 5 mm to about 25 mm (e.g., about 5-10mm, about 5-15 mm, about 5-20 mm). In one embodiment, at least a portionof the delivery device comprises one or more of a NiChrome alloy, silveror a silver alloy. The delivery device, or portions thereof, cancomprise one or more of a solid sheet, a frame, mesh, struts, holes,pores, etc. In one embodiment, a bottom or distal portion of the shaftdefines a bed portion to which a plug (e.g., a cone) of filler material(such as gutta-percha) is mounted. According to several embodiments, thedelivery device extends to the tip of the filler material (or close tothe tip) and wraps around part of the filler material at this distalend. One unique benefit of wrapping around the filler material is thatthis allows for the use of the plugger while the delivery device is in aroot canal. By wrapping around the filler material, a portion of thedelivery device can partially or fully wrap around the filler material.In other words, wrapping around the filler material does not necessarilymean that the filler material is entirely encapsulated. In someembodiments, the delivery device does not extend to the tip of thefiller material, but is sufficiently proximate the tip of the fillermaterial so as to deliver sufficient heat to the filler material. Forexample, in some embodiments, the delivery device extends from about 0.1mm to about 2 mm from the tip of the filler material. The bed portion isheat conductive and/or includes a heating device, to allow for direct orindirect heating of the filler material along the length of the plug offiller material. The bed portion can be provided with one or moreretentive features to help maintain the filler material on the bedportion until the filler material is heated. In accordance with oneembodiment of the system, a temperature sensor can be placed on the bedportion, spaced from the apex or distal end of the plug of fillermaterial. In accordance with another embodiment, a temperature sensorcan be positioned on the plugger which is used in conjunction with thedelivery device. The use of an optional temperature sensor allows for atemperature feedback loop, which allows for controlling of thetemperature to which the filler material is heated.

In some embodiments, the delivery device is received within a holder.The holder, in some embodiments, is configured for compatibility withother devices (such as devices for heating the filler material anddevices for plugging the filler material). The holder, in oneembodiment, removably receives the delivery device. This can be manualor in accordance with one aspect of the system, the holder can beprovided with a retraction device which is operable to axially move thedelivery device relative to the holder. In one embodiment, when thedelivery device is inserted in the holder, the delivery device is in anextended position. The retraction device is operable to retract (pull)the delivery member into the holder as part of the step of separatingthe delivery device from the filler material. Such a retraction devicecan comprise a linkage, a piston, an electromagnetic actuator, or anyother device which can move the delivery device axially.

In accordance with another embodiment, the obturation system comprises aheating circuit and/or a temperature sensor, and a controller. Thetemperature sensor may be positioned to be in thermal communication withfiller material during use and generates a signal indicative of thetemperature of the filler material and/or the surrounding area. Theheating circuit includes a heating member which is regulated by acontroller to deliver heat to the filler material from the bed portionof the delivery device along, or substantially along, the full length ofthe filler material. Hence, the filler material is heated transverselyalong the filler material, rather than longitudinally (i.e., from thetop down). This is particularly advantageous when heating fillermaterials that have limited ability to transfer heat, such asgutta-percha. Because the delivery device partially contacts the fillermaterial along, or substantially along, its full length, it helpsovercome the challenge of currently available heat delivery systems thatattempt to transfer heat downwardly and through gutta-percha. In severalembodiments, the invention is particularly advantageous over heatcarriers that are placed in the center of the filler material and do notextend the length of the filler material. Although such designs maypermit transfer of heat over systems that apply heat at the top of thefiller material, they do not allow for simultaneous molding of thefiller material as heat is applied. Additionally, confirmation of theposition of the filler material is generally not viable, unless, as inseveral embodiments of the invention, the delivery device extends alongthe side and the full length, or substantially the full length, of thefiller material. This feedback of the position of the filler materialupon heat transfer and molding allows for controls to regulate preciseconditions for ideal molding. In one embodiment, the controller is incommunication with both the temperature sensor and the heating circuitto control the heating circuit, and hence the heating of the fillermaterial, in response to the temperature output of the temperaturesensor. If the temperature sensor is on the bed portion of the deliverydevice, the temperature sensor can be proximate the apex of the fillermaterial. The controller controls the heating member to directly heatthe filler material to a temperature at which the material becomesmoldable.

In several embodiments, the controller system can be provided with atimer which is activated by the controller when the temperature sensorreaches the programmed, desired temperature. When the heat has beenestablished and held for a predetermined time, the controller can eithernotify the practitioner for simultaneous manual molding or the holdercan be provided with an automated plugger to mold the filler in place.As these functions are timed, sensed and regulated the controller cannotify the practitioner to manually withdraw the delivery device or theholder can have a system to automatically withdraw the delivery device.The controller can also deactivate the heating circuit after thedelivery device has been removed or after a predetermined time period(e.g., 2-10 seconds) has elapsed.

The system can also include an apex locating circuit which includes thedelivery device, a lip clip and an impedance/resistance monitor.According to some embodiments, the apex locating circuit generates anoutput indicative of the position of the delivery device in the rootcanal. In the apex locating circuit, the delivery device can be theprobe of the apex locating circuit. The delivery device can function asthe probe for such a circuit because it is positioned along the side ofthe filler material and also because it extends the full length, orsubstantially the full length, of the filler material. In oneembodiment, to enable the delivery device to be the probe of the apexlocating circuit, the outer surface of the delivery device bed portionremains exposed when the filler material is mounted to the bed. In thismanner, the outer surface of the delivery device will contact the wallof the root canal when the delivery device is in the root canal.Additionally, at least a portion of the outer surface of the bed portionis electrically conductive. The apex locating circuit generates anoutput indicative of the position of the end of the delivery device in aroot canal based on the resistance/impedance of the apex locatingcircuit. In some embodiments of the system, the controller controls theheating circuit in response to the output of the apex location circuitas well. In particular, according to one embodiment, the controller willnot activate the heating circuit unless the end of the bed portion, andhence the end of the filler material, is within a determined distance ofthe apical foramen of the root canal. Further, the controller canprevent activation of the heating circuit if it is determined that theapical end of the bed portion is in the tissue (e.g., extending throughthe apical foramen of the root canal).

In accordance with one embodiment, the plugger utilized for simultaneousmolding can include one or more temperature sensors (such as athermocouple) positioned at or near its working end so as to detect orsense the temperature of the material that is, for example, contacted bythe plugger surface. The output of the temperature sensor of the pluggeris received by the controller to enable the controller to regulate thetemperature delivery along the device. In addition, the system caninclude an associated display which is in operative communication withthe temperature sensor, such that the sensed temperature of the materialwhich is contacted by the plugger surface is shown on the display. Inone embodiment, the display is located on the handle of the plugger. Inanother embodiment, the display is remote from the plugger handle. Inone embodiment, the plugger comprises a handle and a shaft extendingfrom the handle. The shaft has a proximal end and a distal end, and theplugger defines a working end at the distal end of the shaft. Theworking end of the plugger comprises one or more central posts orstationary plates spaced from the distal end of the shaft by means of apost; and a plurality of movable plates which are movable relative tothe stationary plate/post independently of each other. The movableplates can be connected to the shaft independently of the stationaryplate/post and of each other. The moveable plates, in combination, atleast in part, may surround the stationary plate/post. In oneembodiment, the moveable plates and the stationary plate/post, incombination define a variable plugging surface that enables thecircumferential size and/or shape of the plugging surface to be variedsubstantially instantaneously by contact with the wall of a root canalduring an obturation procedure.

The movable plates can be connected to the distal end of the shaft by aconnector which can be a wire, cable or the like. The connector,according to one embodiment, is made from a material which will deflectaxially when horizontal forces are applied to allow the moveable platesto move in planes generally parallel to each other and to the stationaryplate/post, and which will return to a normal position upon release ofhorizontal deflection forces.

The plugger post and connectors are selected to withstand typicalcompression forces to which they will be subject during an obturationprocedure without buckling (for example, a load of up to about 7 lbs maybe well tolerated).

In accordance with one aspect of the plugger, the moveable platesoverlap each other at least in part and overlap the stationaryplate/post at least in part. Illustratively, the moveable plates aregenerally parallel to each other and generally parallel to thestationary plate/post. As an example, the stationary plate/post can begenerally circular, and the moveable plates can each have an arced outeredge.

In accordance with another aspect of the plugger, the plugger can beprovided with a retraction button on the handle which is operablyconnected to the connectors, such that when the retraction button ispressed, the moveable plates will move toward the stationary plate andpost such that the area of plugger surface is reduced. The retractionbutton can be used to reduce the effective size of the plugger's workingsurface to a smallest possible effective size.

In accordance with another aspect of the plugger, the plugger can beprovided with a pressure transducer to monitor the forces being appliedto mold the filler material. In accordance with one aspect, the appliedforce can be displayed for monitoring by a practitioner duringobturation. In accordance with another aspect, the output of thepressure transducer can be received by the controller, and thecontroller can then control automatic molding of the filler material.

The obturation system can be provided with one or more displays.Displays can be provided on a base unit, and/or on the holder and/or onthe plugger. The displays can be operated to display such things as thetemperature of the filler material, the amount of time at suchtemperatures, the length of the heating period, when to mold manually orwhen automatic molding is occurring, the pressure or force applied tomold the filler material, when withdraw of the delivery device should bemanually withdrawn or when automatically withdrawn, etc. In addition,the system can be provided with an input device (such as buttons) toenable the practitioner to adjust the set temperature to which thefiller material is heated and to adjust the length of time the fillermaterial is heated (e.g., the length of time the heating circuit isactivated). The base unit can also be provided with a display thegraphically shows the location of the delivery device (and hence thefiller material) in the root canal.

In several embodiments, the main controller for the system can belocated either in the holder or the base unit. Alternatively, the systemcan have a single controller for example, in the base unit, and thecomponents can then communicate with the single controller. Suchcommunication can be corded or wireless. Further, some components couldbe corded and others could be wireless.

In several embodiments, the obturation system has several advantages.First, the system delivers heat directly to the filler material along,or substantially along, the entire length of the filler material. Thisovercomes limitations that are present in systems that attempt totransfer heat longitudinally (i.e. through the filler material from topto bottom). This also allows for a more even heating of the fillermaterial, and obviates the need for high temperature heating of thefiller material. This is of clinical importance when using the fillermaterial, such as gutta-percha, as temperature mediated phase changesoccur at higher temperatures which lead to shrinkage when the materialcools. By controlling the temperature of the filler material and notheating the filler material beyond its temperature mediated phasechanges, the physical and mechanical properties of the filler materialare able to be controlled and utilized. In particular, according to oneembodiment, the ability to operate at temperatures below the temperaturemediated phase transitions of the filler material reduces thepossibility of the filler material shrinking as it cools, and thusreduces the potential for void formation between the filler and the rootcanal wall. Further, the system, according to one embodiment,advantageously allows for molding of the filler material while thefiller material is being heated.

Another advantage of several embodiments is the location of the deliverydevice vis-à-vis the filler material. Since the delivery device islocated along the side of the filler material in some embodiments,molding is allowed to occur simultaneously as heat is being delivered.In addition, in several embodiments, because the heat delivery device ison the outer surface of the filler material, it can be withdrawn afterthe heating period has ended and just prior to, or during molding.

Another advantage of several embodiments is the use of an apex locator.In some embodiments, the system utilizes apex location at the time ofobturation or sealing. Apex location is facilitated by the position ofthe delivery device in some embodiments (e.g., extending along, orsubstantially along, the length of the filler material). The use of apexlocation at the time of obturation or sealing (as opposed to duringshaping and disinfecting) enables the practitioner to be fairly certainthat the filler material is properly positioned in the root canal priorto compaction or molding of the filler material. In addition, thisadditional feedback allows for controls to be placed within the overallsystem for a more precise and safe delivery of the filler material.

In several embodiments, a kit is provided. The kit comprises a deliverydevice according to any of the embodiments described herein, fillermaterial according to any of the embodiments described herein, andinstructions for coupling the filler material to the delivery device.Couplers may also be included (e.g., adhesive or other physical couplingmechanisms). In some embodiments, couplers are not needed because thefiller material is configured to mate with the delivery device. Inseveral embodiments, the delivery device may be disposable or reusable.

Briefly, and as discussed more fully below, an obturation system forfacilitating filling of a root canal system, comprises, in oneembodiment, a delivery device that comprises a shaft having a bedportion at a distal end thereof. The bed portion has an inner surfaceand an outer surface. A biocompatible filler material having an uppersurface, a side surface, and a distal end is mounted to the innersurface of the bed. The delivery device has a greater thermalconductivity than the filler material, and is configured to transferheat to the filler material such that the temperature difference alongany two points on the filler material does not exceed more than 20° C.Additionally, the bed portion of the shaft wraps at least partiallyaround the filler material and contacts the filler materialsubstantially along the length of the filler material from the upper endof the filler material to at or proximate the distal end of the fillermaterial to facilitate direct heat transfer to the distal end of thefiller material, thereby facilitating heating of the filler material anddelivery of the filler material to the root canal system. The fillermaterial can comprise gutta-percha.

In accordance with an aspect of the system, the system can furthercomprise a heating device which is configured to deliver heat to the bedportion of the shaft, and thus to the filler material. Further thesystem can include a temperature sensor, and a controller. Thetemperature sensor is positionable to be in heat sensing contact withthe filler material to transmit a temperature signal indicative of thetemperature of the filler material. The controller is configured to bein communication with the temperature sensor to receive the temperaturesignal from the temperature sensor. The controller is further configuredto be in communication with the heating device to control the heatingdevice, and thus the heating of the filler material, in response to theoutput of the temperature sensor.

According to one embodiment, the system can be provided with a timerwhich is in communication with the controller. The controller activatesthe timer when the heating device is activated or upon the fillermaterial reaching a predetermined temperature. The controller thendeactivates the heating device after a predetermined period of time haselapsed. The predetermined period of time can be about 2 seconds toabout 10 seconds.

The system, in one embodiment, can monitor the location of the deliverydevice in the root canal, and the controller prevents activation of theheating device unless the controller determines the apex of the fillermaterial to be within a predetermined distance of an apex of a preparedroot canal. In accordance with one aspect, the controller automaticallyactivates the heating device to heat the filler material when it isdetermined that the apex of the filler material is at the apical end ofa root canal or within about ¼ mm of the apical foramen of the rootcanal. Further, the controller can prevent activation of the heatingdevice if it is determined that the delivery device extends through anapical foramen of the root canal.

The heating device is configured to deliver heat to the filler materialto heat the filler material to a temperature of less than 75° C. to theupper surface of the filler material, e.g., between about 39° C. andabout 65° C. or between about 42° C. and about 65° C., or between about39° C. and about 60° C.

The system can include one or more temperature sensors located on thedelivery device.

The system can, in an embodiment, comprise a plugger having a pluggersurface configured to contact the filler material. The plugger caninclude a temperature sensor and/or a pressure transducer located on theplugger surface. Further, the plugger can be provided with a vibrationgenerator positioned on the plugger to induce vibrations in the pluggersurface.

A system as described above can further comprise an apex locationconfirming circuit. The apex location confirming circuit comprises thedelivery device and a lip clip. The delivery device comprises anelectrically conductive member extending along at least the outersurface of the delivery device bed portion and which will contact asurface of the root canal when the device is inserted in the root canal.The apex location confirming circuit generates a location signalindicative of the location of the delivery device in the root canalbeing treated. The controller is in operative communication with theapex location confirming circuit to receive the location signal.

In one embodiment, the system further comprises a holder adapted toremovably receive the delivery device. In one embodiment, the holderincludes the heating device to deliver heat to the delivery device andhence the filler material.

The holder can be provided with an axially movable retractor to whichthe delivery device is removably connectable. The retractor, in oneembodiment, is operable to retract the delivery device from an extendedportion to a retracted position and is being adapted to move thedelivery device axially within the root canal a distance sufficient towithdraw the delivery device from the filler material. A controller isin operative communication with the retractor. The controller emitting acommand to automatically activate the retractor after the fillermaterial has been heated to a predetermined temperature for apredetermined period of time.

In an aspect of the system, the system comprises a plugger, a pluggerdriver and a controller. The controller is in operative communicationwith the plugger driver, and the plugger driver is controlled by thecontroller to axially move the plugger. The controller is configured toemit a command to activate the plugger driver to apply a moldingpressure on the filler material while a heating device is activated. Theplugger can be provided with a pressure transducer which generates asignal indicative of the pressure or force applied by the plugger on thefiller material. The controller is in operative communication with thepressure transducer to control the plugger driver in response to thesignals from the pressure transducer.

In accordance with another aspect of the system, the obturation systemcomprises a delivery device and a biocompatible filler material. Thedelivery device comprises a shaft having a bed portion at a distal endthereof, and which has an inner surface and an outer surface. The fillermaterial comprises an upper surface, a tapered side surface and a distalend. The delivery device has a greater thermal conductivity than thefiller material, and is configured to transfer heat to the fillermaterial such that the temperature difference between any two points onthe filler material does not exceed more than 20° C. The bed portion ofthe shaft extends along an outer surface of the filler material andcontacts the filler material from the upper surface of the fillermaterial to within about 2 mm from the distal end of the filler materialto facilitate heat transfer to the distal end, thereby facilitatingheating of the filler material and delivery of the filler material tothe root canal system. The delivery device is comprised of platinum,silver, gold, copper, or aluminum or alloys thereof or other thermallyconductive and/or electrically conductive metals or alloys.Alternatively, the delivery device can be coated, at least in part withplatinum, silver, gold, copper, or aluminum or alloys thereof or otherthermally conductive and/or electrically conductive metals or alloys.The filler material comprises a cone-shaped plug of gutta-percha.

The system, in one embodiment, further comprises a heating device whichis configured to deliver heat to the bed portion of the shaft, and thusto the filler material.

The system further comprises a plugger and a controller, the controllerbeing in operative communication with the plugger, and configured toemit a command to activate the plugger to apply a molding pressure onthe filler material while a heating device is activated.

A method of facilitating filling of a prepared root canal system isdisclosed in one embodiment and comprises the steps of confirming theposition of filler material in the prepared root canal; activating aheating device to deliver heat to heat the filler material to atemperature in the range of about 39° C. to about 65° C. to heat thefiller material in situ in the canal; and contacting the filler materialwith a plugger to facilitate molding of the filler material into theroot canal system. The method can further include a step of maintainingthe filler material at a temperature of about 39° C. to about 45° C. fora predetermined period of time.

A delivery device for delivering filler material to a prepared rootcanal as part of an obturation procedure is disclosed. In oneembodiment, the delivery device comprises a shaft portion; and a bedportion at a distal end of the shaft portion. The bed portion comprisesa filler material receiving surface and a pair of side edges. The fillermaterial receiving surface is generally concave in shape. The side edgesof the bed portion can slope downwardly and inwardly toward each other,such that the bed portion is generally triangular in shape. The bedportion can have a tapered outer surface. The generally concave shape ofthe bed defines a curvature; and this curvature can correspond generallyto the curvature of a plug of filler material to be mounted on the bed.

The delivery device can comprise at least one retention feature tosecure filler material to the bed. The retention feature can comprise(i) one or more holes which extend through the bed surface, and/or (ii)cutouts/indents formed in the side edges of the bed, and/or (iii)texturing of the bed surface, and/or (iv) bending of the side edgesinwardly, and/or (v) flashing from the formation of the holes orcutouts/indents, and/or (vi) an adhesive and/or (vii) one or more rims.

The delivery device can include a connecting portion at a proximal endof the shaft portion. The connecting portion is adapted to connect thedelivery device to a holder. The connecting portion can comprise a lockfor removably securing the device to the holder. The lock can compriseone of a bayonet slot and a pin or one of a spring biased member and agroove which receives a spring biased member. The connecting portion cancomprise a hollow tube.

According to one aspect, the delivery device is made from anelectrically conductive material or has an electrically conductivecoating on an outer surface of the device.

According to another aspect, the delivery device is made from a made aheat conductive material. The delivery can include a heating elementlocated at the bed portion.

The delivery device can be provided with a plug of a filler materialthat is secured to the bed portion. The plug of filler materialcomprises an outer surface which is in contact with the receivingsurface of the bed portion. The bed portion has an outer surface whichremains exposed when the filler material is secured to the bed portion.A distal end of the bed is proximate the bottom of the plug of fillermaterial. Alternatively, the practitioner can secure the plug of fillermaterial to the bed of the delivery device prior to insertion of thedelivery device and the filler material into the root canal. As afurther alternative, during an endodontic (i.e., root canal) procedure,the practitioner can insert the delivery device into the prepared canalwithout the plug of filler material. The desired filler material plugcan then be inserted into the canal. In this instance, the shape of thedelivery device will act as a guide to facilitate insertion of the plugof filler material into the prepared root canal.

In accordance with another aspect, a system for filling and sealing anapical end of a prepared root canal is disclosed. The system comprises adelivery device and a heating circuit. The delivery device comprises ashaft portion and a bed portion at a distal end of the shaft portion.The bed portion has an inner surface and an outer surface. The innersurface is adapted receive filler material, and the outer surfaceremains exposed when the filler material is mounted to the innersurface. The bed has a length at least substantially equal to the lengthof the filler material to be mounted to the bed. The heating circuitcomprises a heat device operable to deliver heat to at least the innersurface of the bed, such that the filler material is heated transverselysubstantially along the length of the filler material when the heatingcircuit is activated. At least the bed of the delivery device is madefrom a heat conductive material.

In accordance with an aspect of the system, the heating circuit cancomprise a heating element located at the bed.

In accordance with an aspect of the system, the system further includesa controller which is in communication with the heating circuit toactivate and deactivate the heating circuit. The controller, uponactivation, activates the heating circuit for a predetermined period oftime. The system can include a temperature sensor in communication withthe controller and which is in heat transfer relationship with thefiller material when in use. The temperature sensor transmits to thecontroller a signal indicative of the temperature of the filler materialbeing heated, and the controller controls the heating circuit inresponse to the signal from the temperature sensor.

In accordance with an aspect of the system, the system can include anapex locating circuit which is in communication with the controller. Theapex locating circuit transmits a signal indicative of the location ofthe delivery device in a root canal, and the controller activates theheating circuit in response to a location signal received from the apexlocating circuit. The delivery device can comprise a probe of the apexlocating circuit.

A method for heating a plug of filler material in situ in a root canalis disclosed wherein the filler material, in one embodiment, is coupledto the inner surface of a bed of a delivery device such that an outersurface of the delivery device bed remains exposed, and wherein the bedhas a length at least substantially equal to the length of the fillermaterial. The method comprises transferring heat from the bed to thefiller material to transversely heat the filler material substantiallyalong the length of the filler material to a temperature slightly abovethe molding temperature of the filler material. In accordance with oneaspect of the method, the filler material comprises gutta-percha and themethod comprising heating the filler material to between about 37° C.and about 65° C., or between about 39° C. and about 50° C. In oneembodiment, the step of transferring heat from the bed to the fillermaterial comprising activating a heat element located at the bed. Inanother embodiment, the step of transferring heat from the bed to thefiller material comprising heating the bed, the bed being made of a heatconductive material. The heating step is carried out for less than 10seconds, e.g., about 3-5 seconds. In accordance with an aspect, theheating step is electronically controlled by a controller, and thecontroller initiates the heating step in response to a signal receivedfrom an apex locating circuit confirming that the charge of fillermaterial is at an apex of a prepared root canal.

A method of sealing at least the apical end of a prepared root canal isdisclosed. The method, in one embodiment, comprises heating abiocompatible thermoplastic filler material in a prepared root canal toa moldable temperature. The heating step comprises heating the fillermaterial from a side of the filler material and along substantially thefull length of the filler material. The method further includes at leastpartially molding the heated filler material into the apical end of theroot canal while the filler material is being heated tothree-dimensionally seal the apical end of the root canal. Heating ofthe filler material comprises heating the filler material such that itis substantially of a constant temperature throughout the fillermaterial, such that there are substantially no temperature gradients inthe filler material, either from side-to-side or from top-to-bottom. Inaccordance with an aspect of the method, the filler material is agutta-percha. Further, the filler material can be a cone-shaped plug ofgutta-percha. If the filler material is gutta-percha, gutta-perchafiller material is heated to a temperature of between about 37° C. andabout 65° C., or between about 39° C. and about 50° C., or between about39° C. and about 45° C. The method can further comprise a step ofmonitoring the temperature of the filler material and controlling theheating of the filler material in response to the monitored temperatureof the filler material.

In accordance with an aspect of the method, the method includes a stepof confirming that the filler material is within a predetermineddistance of the apical end of the root canal prior to commencement ofthe step of heating the plug of filler material. Stated differently, theheating step is not initiated unless it is determined that the end ofthe plug of filler material is within a determined distance of theapical end of the root canal.

In accordance with one aspect of the method, the filler material ismounted to a delivery device, and the step of applying heat to thefiller material comprises heating a distal end of the delivery device.The method further includes a step of withdrawing the delivery devicefrom the filler material after the filler material has been heated to adesired temperature for a predetermined period of time, which can beabout 2 to about 10 seconds. In accordance with an aspect of the method,the delivery device is automatically moved axially in the canal toseparate the delivery device from the filler material.

In one embodiment, the step of molding the filler material comprisesinserting a plugger into the root canal prior to commencement of thestep of heating the filler material. In an embodiment, the method caninclude vibrating a working end of the plugger while the plugger ismolding the filler material.

A holder for a delivery device for delivering filler material into aprepared root canal is disclosed. The holder, in one embodiment,comprises a body, a mounting portion adapted to removably receive thedelivery device; and a heating circuit having a heating device whereinthe heating device is positioned to be in thermal communication with thedelivery device when the delivery device is mounted to the holder.

In a first illustrative embodiment of the holder, the mounting portioncomprises a pair of arms extending from the body; the arms beingdeflectable to be urged together under a squeezing pressure. In thisembodiment, the arms each have a grasping portion at a distal end of thearms which is adapted to grasp the delivery device when the arms aresqueezed together.

In an alternative illustrative embodiment of the holder, the mountingportion comprises an elongate nose extending from the body. The nose canbe comprised of a heat conductive material, in which case, the heatingdevice is operable to transmit heat to the nose. In accordance withanother aspect of this second embodiment, the nose is at least in partelectrically conductive.

In a further illustrative embodiment of the holder, the mounting portioncomprises a channel in the holder body which is sized to removablyreceive a distal end of the delivery device. In this embodiment, theheating device is proximate the channel. In one aspect, the holder cancomprise a retracting member in the channel which is movable axiallyrelative to the chamber and which is adapted to be removably connectedto the delivery device when the delivery device is received in themounting portion.

In accordance with a further aspect of the holder, the holder caninclude a plugger which is axially movable relative to the channel. Theholder includes a plugger driver operable to axially move the pluggerbetween an extended position and a relaxed position.

In accordance with another aspect of the holder, the holder can includeat least a portion of an apex location circuit.

An endodontic plugger is disclosed which comprises, in one embodiment, ahandle and a shaft extending from the handle. The shaft has a proximalend and a distal end, and the plugger defines a working end at thedistal end of the shaft. The working end of the plugger comprises aplurality of movable plates that are independently operably connected tothe shaft. The plurality of moveable plates, in combination, defines atleast a portion of a variable plugging surface. The moveable plates areindependently movable relative to each other, enabling thecircumferential size and/or shape of the plugging surface to be variedsubstantially instantaneously due to contact with the wall of a rootcanal during an obturation procedure.

In accordance with an aspect of the plugger, the endodontic plugger canfurther include a stationary surface spaced from the distal end of theshaft by means of a post. The stationary surface can be generallycircular. The movable plates surround at least a portion of thestationary surface and are movable relative to the stationary surface.In an embodiment, the stationary surface can be defined by a platemounted to a distal end of the post.

In accordance with an aspect of the plugger, the moveable plates aremovable in two degrees of freedom.

In accordance with an aspect of the plugger, the moveable plates aregenerally parallel to each other.

In accordance with an aspect of the plugger, the moveable plates overlapeach other in part.

In accordance with an aspect of the plugger, the moveable plates eachhave an arced outer edge.

In accordance with an aspect of the plugger, the moveable plates areindependently connected to the shaft by a connector, there being atleast one connector for each moveable plate. The connector is made froma material which will deflect to allow the moveable plates to move inplanes generally parallel to each other, and will return to a normalposition upon release of deflection forces. The connectors are made froma material which can withstand typical compression forces to which theconnectors will be subject during an obturation procedure withoutbuckling. In accordance with an aspect of the connectors, the connectorsbuckle if a load of more than a predetermined amount is applied to theplugger. The predetermined amount of load is up to about 7 lbs. Inaccordance with a further aspect of the connectors, the connectors eachextend generally downwardly and outwardly from the distal end of theshaft to the moveable plates.

In accordance with another aspect of the plugger, the plugger comprisesa retraction button on the handle which is operably connected to theconnectors; whereby when the retraction button is pressed, the moveableplates will move inwardly toward each other such that the area ofplugger surface is reduced.

In accordance with an aspect of the plugger, the plugger can comprise atemperature sensor on the plugger surface and an associated display. Thetemperature sensor is in operative communication with the display, suchthat the display displays the temperature of the material which iscontacted by the plugger surface. The display can be located on thehandle of the plugger or remote from the plugger handpiece. Thetemperature sensor can be located on the stationary plate. Thetemperature sensor can be a thermocouple.

In accordance with an aspect of the plugger, the plugger can furthercomprise a pressure transducer which is positioned on the plugger so asto generate a signal indicative of the force applied to an object by themoveable plates. The pressure transducer can be in communication with anassociated display, such that the display displays the pressure or forceapplied to the material which is contacted by the plugger surface. Thedisplay can be on the plugger handle or remote from the plugger.

In accordance with an aspect of the plugger, the plugger can comprise avibration generator. The vibration generator is positioned on theplugger and is adapted to induce vibrational energy in the movableplates.

In accordance with an aspect of the plugger, the endodontic pluggercomprises a handle and a shaft extending from the handle. The shaftcomprises a proximal end and a distal end, wherein the distal end of theshaft defines a plugger surface. A temperature sensor is located on theplugger in a position to place it in heat transfer relationship with amaterial to be contacted by the plugger surface and is configured toemit a signal indicative of a temperature of the material contacted bythe plugger surface. The plugger additionally includes a display inoperative communication with the temperature sensor; the display beingconfigured to display the temperature of the material contacted by theplugger surface. In an embodiment, the temperature sensor is located onthe plugger surface. The display is located on the handle of the pluggeror is remote from the plugger handpiece. The display operativelycommunicates wirelessly with the temperature sensor. The temperaturesensor can be a thermocouple.

A method of obturating a root canal that has been shaped, cleaned anddried is disclosed. The method comprises, in one embodiment, the stepsof engaging a plug of heated filler material placed in the root canalwith a working surface of a plugger, applying a molding/packing force tothe plug of filler material while the filler material is above apredetermined temperature, monitoring the temperature of the fillermaterial while the surface of the plugger is in contact with the fillermaterial, and stopping the application of the compressive force to thefiller material after it is determined that the temperature of thefiller material has fallen below a predetermined temperature.

In accordance with one aspect of the method, the plugger comprises ahandle and a temperature sensor at the working surface of the plugger.The temperature sensor is in operative communication with a display andtransmits a temperature signal. The display displays the temperature ofthe filler material based on the signal from the temperature sensor. Themethod comprises displaying the temperature of the filler material whilethe surface of the plugger is in contact with the filler material. Thetemperature sensor can provide data to a controller to regulate thetemperature delivered to the filler material.

In accordance with an aspect of operating the plugger, the methodcomprises displaying a temperature of a root canal filling materialwhile the plugger is in contact with the root canal filling material.The plugger can comprise a handle with a display on the handle, in whichcase, the method comprises displaying the temperature of the fillingmaterial on the display.

In accordance with a method of operating the plugger defining a pluggersurface during an obturation procedure, the method comprises, in oneembodiment, automatically and substantially instantaneously adjustingthe size and/or shape of the plugger surface in response to thecross-sectional size and/or shape of a root canal as the plugger surfacepasses along the root canal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative embodiment of anobturation system;

FIG. 2 is a perspective view of an illustrative embodiment of a holderof the obturation system

FIGS. 3A-C comprise a perspective, cross-sectional schematic andelevational schematic views of an illustrative embodiment of adisposable filler material delivery device of the obturation system;

FIG. 4 is an enlarged fragmentary view of the holder in the process ofgrasping the delivery device;

FIG. 5 is a block diagram of the control system of the obturationsystem;

FIGS. 6A and 6B are basic electrical schematics for the apex locatingcircuit and the heating circuit, respectively, used in the holder;

FIG. 7A is a perspective view of an alternative embodiment of theobturation system showing a delivery device and holder therefore, aplugger and a lip clip, with the delivery device and plugger shown in aroot canal;

FIG. 7B is a side perspective view showing connection of cords for thelip clip and holder;

FIGS. 7C-E are perspective, side elevational and front elevationalviews, respectively of a base unit of the obturation system of FIG. 7A;

FIGS. 8A-B are perspective and elevational views of a delivery device ofthe obturation system of FIG. 7A;

FIGS. 9A-C are horizontal cross-sectional views of the delivery devicetaken at lines A-A, B-B and C-C of FIG. 8A;

FIG. 9D is an enlarged view of the distal end of the delivery deviceshowing the position of a heat sensing element on a plug/cone of fillermaterial;

FIGS. 10A and B are side elevational and perspective views of analternative delivery device for use with the system of FIG. 7A;

FIG. 11 is an enlarged perspective view of a bed portion of the deliverydevice of FIG. 10A;

FIG. 12 is a plan view of the bed portion of the delivery device of FIG.10A, showing two types of retentive features which can be applied to thebed portion;

FIG. 13 is a schematic vertical cross-sectional view of the distal endof the delivery device of FIG. 10A;

FIGS. 14A-B are horizontal cross-sectional views through the bed portionof the delivery device of FIG. 10A, showing two alternative retentivefeatures

FIGS. 15 and 16 are enlarged perspective views showing the connectingportion of the delivery device of FIG. 10A;

FIG. 17A is a perspective view of a second illustrative embodiment ofthe holder;

FIGS. 17B-D are rear, front, and side elevational views, respectively,of the holder of FIG. 17A;

FIG. 17E is a schematic cross-sectional view of the holder of FIG. 17A;

FIG. 18 is a schematic cross-sectional view of a variation of the holderof FIGS. 17A-E;

FIG. 19 is a perspective view of a plugger for use with the obturationsystem;

FIG. 20 is a cross-sectional view of the plugger taken along line A-A ofFIG. 19;

FIG. 21 is an enlarged side elevational view of the working end of theplugger taken at circle B of FIG. 19, showing the individuallyadjustable plates of the plugger in an opened or expanded configuration;

FIG. 22 is an enlarged perspective view of the working end of theplugger;

FIG. 23 is a plan view of the working end of the plugger with themoveable plates in an open or expanded configuration;

FIG. 24 is a plan view of the working end of the plugger with themoveable plates of the plugger in oval configuration;

FIG. 25 is a plan view of the working end of the plugger with themoveable plates in a closed or retracted configuration;

FIG. 26 is a view of the plugger similar to that of FIG. 22, but showingthe position of a temperature sensor on the plugger;

FIG. 27 is a view of a plugger with a standard end and provided with atemperature sensor;

FIG. 28 is a view of the working end of the plugger with an alternativeconfiguration of the moveable plates, wherein gaps exist between themoveable plates and a stationary plate when the moveable plates are inthe expended position;

FIG. 29A is a schematic drawing of a further embodiment of theobturation system;

FIG. 29B is a perspective view of the holder and delivery device of thesystem of FIG. 29A;

FIG. 29C is an fragmentary, enlarged perspective view of the holder ofFIG. 29B showing the tip of the holder with an automatic pluggerextending from the holder toward the filler material on the deliverydevice;

FIG. 30 is a schematic of a control system for the obturation system ofFIG. 7A;

FIG. 31A is an x-ray showing the delivery device of FIG. 10 in a rootcanal with an associated plugger in engagement with a plug of fillermaterial;

FIG. 31B is an x-ray similar to that of FIG. 31A, but without theplugger;

FIG. 31C is an x-ray of a tooth having the apex of the root canal filledusing the obturation system;

FIG. 32 is another x-ray showing the delivery device and plugger in aroot canal during an obturation procedure

FIGS. 33A-K contain a series of schematic drawings showing theprogression of a filling/sealing procedure in a root canal using thedelivery device of FIG. 10 connected to a further embodiment of theholder and the plugger of FIG. 19; and

FIG. 34 is a flow chart of the process carried out by the control systemof either FIG. 5 or FIG. 29.

Corresponding reference numerals will be used throughout the severalfigures of the drawings.

DETAILED DESCRIPTION

In a root canal procedure, the practitioner prepares an access cavitythrough the crown of the tooth to the pulp chamber in the canal(s). Thepractitioner then removes the pulp from the canal(s) and shapes thecanal(s). Shaping of the canal(s) is typically performed with a seriesof metal files. Chemical reagents are used to disinfect, dissolve andclean all aspects of the root canal system. Root canals do not define asingle smooth path. Canals are often curved, rather than straight. Inaddition the root canal system may include fins, webs, cul-de-sacs andlateral canals. Ideally, the shaping, cleaning and disinfecting stageremoves the pulp, bacteria and other irritants from all aspects of theroot canal system, including any fins, webs, cul-de-sacs and lateralcanals that may be part of the root canal system, not just from the maincanal.

After the canal system has been shaped, cleaned, disinfected and dried,the root canal system is ready to be sealed with a filler/sealingmaterial. Gutta-percha is (and has been) the most common material usedfor sealing the root canal system. Once the root has been filled andsealed, the access cavity formed in the crown is restored with a bondedrestoration.

There are several methods employed to seal root canal systems. Theoldest and still most common way to seal a root canal system is referredto cold lateral condensation. This technique places a piece of fillermaterial in a prepared canal that roughly matches the shaped canal.Subsequent pieces of filler material are jammed in the canal after aninstrument laterally jams the material to the side. This technique hasdownfalls in its ability to three-dimensionally seal the vast array ofrandom internal anatomy present. Another common technique is to simplyplace a single cone-shaped plug of filler material into the canal.Although most techniques discussed here utilize a sealer material aswell, this technique relies more heavily on the sealer to fill in thethree-dimensional spaces of the canal. This technique has limitations inits ability to accurate and densely seal root canal systems.

In some cases, filler material is commonly provided as a generallycone-shaped plug, and the filler material plugs are provided in varyingdiameters and tapers. The practitioner selects the filler material plugbased on its diameter and taper, and cuts the filler material plug tolength so that it fits the shape of the apical end of the preparedcanal. This technique of fitting a so-called “master cone” can be timeconsuming and subject to error. Typically, the filler material plug isadjusted (trimmed and sized) based on information the practitioner gainsin the shaping procedure. For example, the practitioner attempts tomatch the instrument/file used to shape the canal during preparation forobturation. The practitioner typically must utilize knowledge of thelength of the canal gained in the preparation of the canal (so that thepractitioner knows how long the filler material plug should be). Duringthe shaping of the canal the practitioner can use an apex locator. Thisapex locator is able to give the practitioner information as to thelength of the main canal by analyzing changes in resistance andimpedance measured with the use of files during the shaping procedure.This apex locator is a separate tool, and used in conjunction withelectrically conductive devices, such as files, that extend to the endof the root canal. Currently, to the best of Applicant's knowledge, apexlocator technology is not used in conjunction with filler materials. Thepractitioner also determines that the filler is properly fitted to theapical extent of the canal through a tactile feeling of “tug back”. Thisarbitrary feeling aims to confirm that the filler material fits well atthe estimated length of the canal. Once the filler material plug hasbeen appropriately sized, it is heated from the top of the fillermaterial and pressed to mold the filler material plug to seal the rootcanal. This technique has limitations in the ability to directly deliverheat to deep levels of the filler material. For instance, gutta-perchadoes not have the capacity to transfer heat past a few millimeters.Therefore, in an attempt to heat the entire plug, the top of the plug istypically heated to high temperatures (e.g., 200-300° C.) even thoughgutta-percha has been shown to be moldable at temperatures as low as 39°C. A further complication of such high temperature is thatgutta-percha's temperature mediated phase transition has been shown tooccur at levels as low as 42° C. (depending on formulation and brand)with an additional amorphous temperature mediated phase change thatoccur at levels reported as low as 53° C. Again, the actual temperaturesat which gutta-percha goes through these phase transitions are within arange and reported differently based on the variation of gutta-perchaevaluated. When gutta-percha is heated beyond these temperature mediatedphase transition temperatures, the gutta-percha will shrink as it cools.This shrinkage can cause gaps to form between the gutta-percha fillerand the root canal wall. As can be appreciated, the formation of gaps ina filled root canal is undesirable. Hence, the temperatures used by suchheating devices are well in excess of temperatures needed for moldinggutta-percha and they are far above gutta-percha's temperature mediatedphase transition temperatures which lead to shrinkage. Severalembodiments of the present system are particularly advantageous becausemoderate to low temperatures (e.g., in the range of about 39° C. toabout 65° C., and up to about 100° C.) may be used. Higher temperaturesmay be used in one embodiment, but are typically not needed.

Another device commonly used to seal root canal systems, which utilizesvery high temperatures, is a filler material extrusion device. Extrusiondevices necessitate heating the filler material, namely gutta-percha, tohigh enough temperatures (e.g., above 160° C.) to allow for the fillermaterial to flow through a chamber. These devices are most commonly usedto fill coronal aspects of a canal once the apical end of the canal issealed in an effort to not inadvertently flow excessive material beyondthe canal.

Additionally, delivery devices have been developed that allow for a“carrier” to deliver the filler material into the root canal. Once thefit is estimated to be appropriate the device is heated in an oven, andthen inserted into the canal. Although this technique allows for a morethorough heating of the filler material there are many downfalls to thistechnique. First, the material is in two different states from when itis estimated for fit to when it is put in for final placement; that is,it is cold and solid when initially estimated to fit and then warm andmore liquid (or more fluid) when inserted into the canal. A commoncomplication is the filler material coming off during the finalplacement. Second, this final placement is a one shot deal. There islittle or no room for adjustment if the final placement ends short orlong of the desired position. Third, as can be appreciated, when aheated plug is inserted in the canal, there is no other source of heat,and the filler material plug must be molded into the canal before itcools. Fourth, there are disadvantages related to the retention of thecarrier, which include, but are not limited to being in the way of otherrestorative materials use to bond within and over the sealed root canal.

Finally, removable heat delivery devices have been mentioned. Theseremovable delivery devices are theorized to allow for placement of thefiller as well as for delivery of heat to the filler. These devices arecentrally placed within the filler material and do not extend to thetip. Although this would allow for a more controlled delivery of heatwhile the device and filler material are within the root canal, they donot allow for molding to occur while the delivery device is in place;that is, a molding device, such as a plugger, cannot be brought into theroot canal until the centrally placed delivery device is withdrawn.Moreover, since this type of system does not position the deliverydevice at the outer border of the filler material and as it does notextend to, or near to, the tip of the filler material the use of theapex locator during placement and at the beginning of themolding/sealing of the root canal is not possible.

Several embodiments of the invention are particularly advantageousbecause the delivery device enables the practitioner to perform an apexlocation when the filler plug is in the canal, enabling the practitionerto be more certain of the position of the plug in the canal prior tomolding of the plug. Several embodiments provide a system that allow formolding at the time of the heat delivery and at the time the deliverydevice is withdrawn. Some embodiments comprise a device that allows fora direct temperature delivery along the entire length, or substantiallyalong the length, of the filler material, thereby eliminating the needfor the high heat used by currently available heating devices. In oneembodiment, the invention is beneficial because it has some or all ofthe advantages described above.

In one embodiment, the device (i) can be used to confirm that the fillermaterial is properly positioned in the root canal at the time of moldingof the filler material, and (ii) enables for a thorough and preciseheating of the filler material along the entire length, or substantiallythe entire length, of the plug of filler material in situ and whichwould avoid the need for high temperatures.

In addition to a delivery device system which allows for thesefunctions, it would be advantageous, in some embodiments, to increasethe functionality of pluggers currently employed. During filling andsealing of the root canal, the practitioner positions filler material inthe canal and attempts to mold the filler material into the canal sothat the filler material fills and conforms to the canal space. Often aninstrument, such as a plugger, is used to mold the filler material intothe root. The plugger typically has a flat end so that it can press thefiller material in place into the prepared, cleaned/disinfected anddried canal. The plugger has an end with a set or fixed diameter whichis typically round and which is smaller in diameter than the diameter ofthe root canal, and smaller in diameter than the coronal-most end of thefiller material plug. As can be appreciated, when the heated fillermaterial is compressed in the root canal, the filler material will notbe constrained axially. That is, nothing prevents the filler materialdisplaced by the plugger from moving coronally axially (i.e., toward thetooth crown) in the canal around the plugger. This coronally-directedaxial flow of the filler material in the root canal makes proper fillingand sealing of the root canal difficult.

A prepared canal is tapered, and has a diameter that decreases from topto bottom. Pluggers, as noted, have ends that are of a determineddiameter, and come in different diameter sizes (e.g., 1 mm, 0.9 mm, 0.5mm, etc.) Because the diameter of the plugger is set, a specific pluggercannot be pushed too far into the canal. If the plugger is pushed toofar into the canal, the plugger will engage the wall of the root canaland exert lateral forces against the root canal wall, which can lead toa fracture of the root canal. The practitioner therefore selects aseries of pluggers of different sizes to compress the filler material,and monitors the depth to which the pluggers are inserted into the canalin an effort to avoid inadvertent locking of the plugger into the rootand excessive application of lateral forces to the root canal wall.

Several embodiments of the present invention provide a plugger thatfacilitates a safer method for molding filler material. In oneembodiment, the plugger universally adapts/conforms to the various rootcanal shapes/sizes present in the prepared root canal. This may alsoincrease forces of safe compaction by reducing the amount of fillermaterial moving axially and coronally around the plugger as the fillermaterial is pressed into the canal. In one embodiment, the plugger wouldalso simplify the obturation process in that the practitioner could usea single plugger, rather than the multiple pluggers which are currentlyused.

Referring now to the drawings, an illustrative embodiment of anobturating system 10 is shown generally in FIG. 1. The system 10comprises a base 12 and a holder 14 for a filler material deliverydevice 16. The base 12 comprises a body 20 having a side surface 22, afront surface 24 and a top surface 26. The base 12 is shown to have asloping top surface and a side surface which curves from one end of thefront surface to the other, to give the base a pleasing aestheticappearance. The base 12 can be given virtually any desired shape. Areceptacle 28 is formed in the top surface of the base and extends intothe base 12. The receptacle 28 is shaped to receive the holder 14, andsized such that the holder 14 can stand on its own when inserted in thereceptacle 28. Optionally, a display 30 is mounted to the front of thebase 12. The display 30, as shown, is pivotable about the bottom of thedisplay, such that the angle of the display relative to the vertical canbe altered, to enable a practitioner to adjust the viewing angle of thedisplay. The display 30 may include an image 32 of a tooth with alighted scale 34 in the canal of the tooth. As will be explained below,the lighted scale indicates how far into the root canal the deliverydevice has been inserted. The scale 34 may include a “green” or “go”section 34 a proximate the apex of the root canal which will beactivated when the system senses that the apex or distal end of thedelivery device 16 is in a “favorable zone”, that is, when the distalend of the delivery device is within a predetermined distance of theapex (or apical foramen) of the canal (about ¼ mm-½ mm from the apicalforamen) and not extending through the apical foramen or otherwise incontact with tissue.

Although not shown, the base 12 includes an electrical cord to enablethe base to be plugged into an electrical wall socket. Alternatively,the base could be battery powered (so as to be cordless). Internally,the base includes a circuit board having a controller 36 (FIG. 5) whichis in electrical communication with the display 30 to drive the display30. The base controller 36 is also in communication with the holder 14to receive at least location data from an apex location circuit in theholder, which is described below. This location data will be used by thecontroller 36 to drive the display 30. The connection between the holder14 and the base unit 12 (and hence the controller 36) can be a cordedconnection or a wireless connection. If the connection is wireless, thebase unit 12 and holder 14 will each be provided with a transceiver toenable the controller 36 to transmit commands to, and receive data from,the holder 14. In addition, if the holder is wireless, the base 12 willinclude a charging circuit to charge batteries contained within theholder 14. Such a charging circuit can include appropriate contacts inthe receptacle 28.

The holder 14 is shown generally in FIG. 2. As seen, the holder 14comprises a body 40 with two arms 42 extending from the forward end ofthe body 40. The arms 42 are flexible and/or moveable such that they canbe urged toward each other to be used like a tweezers or forceps. Whenreleased, the arms 42 will spring back to a rest position in which thearms are generally normal to the end of the holder body 40. The body 40is shown to be generally oblong in cross-section, such that it has agenerally flat surface 40 a. A display 44 formed in the surface 40 adisplays data regarding the obturation procedure, such as thetemperature of the filler material cone or plug proximate the end of thefiller material (e.g., cone/plug), as will be explained in more detailbelow. The holder body 44 is also provided with input means 45, in theform of buttons, to program a set temperature for a heating circuitand/or a time limit for a timer.

The holder arms 42 each include an elongate portion 42 a with a fingeror grasping member 42 b extending from the end of the elongate portion42 a. The fingers 42 b each have a concave inner surface 42 c (as bestseen in FIG. 4) to facilitate grasping of the delivery device 16. Tothis end, the concave inner surfaces 42 c of the arms 42 face eachother. The fingers 42 b are shown to be angled relative to the elongateportions 42 a. The angle defined by the fingers 42 b and the elongateportions 42 a of the arms 42 is formed to facilitate insertion of thedelivery device 16 into a tooth canal while holding the holder 14 in acomfortable manner. The holder 14 can be provided with finger rests orgrips 43 partway along the length of the arm. One of the grips 43 may beprovided with a switch 46 (FIG. 6B), such as a pressure switch which canbe used to activate a heating circuit and/or an apex location circuit,or a complete obturation cycle, as will be described more fully below.

The system 10 also includes a lip clip 48 (FIG. 6A) which forms part ofthe apex locating circuit. The lip clip 48 can be connected (preferably,removably connected) to the holder by means of a cord. Alternatively,the lip clip can be connected to the base unit 12 by a cord.

Turning to FIGS. 3A-C, the delivery device 16 comprises a cylindricalbody or connecting portion 50 and a shaft 52 extending from the body orconnecting portion 50. The shaft 52 comprises a stem portion 52 aextending from the connecting portion 50 and a mounting or bed portion52 b at the distal end of the shaft to which a plug or cone 54 of fillermaterial (such as a gutta-percha) is mounted. The filler material 54 iscomprised of a biocompatible thermoplastic in one embodiment. Forexample, the filler material can be comprised of a gutta-percha (e.g.,polyisoprene). Other biocompatible thermoplastic sealing compositionscould be used instead of, or in addition to, gutta-percha. Theconnecting portion 50 is shown to be generally cylindrical (but can bedifferently shaped if desired), and is sized to be grasped by apractitioner. The shaft 52 is shown to comprise a generally circularrod, but this could take on any configuration. For example, the shaft 52could be circular and thin in configuration so as to not get in the wayof a plugger also coming into position for molding when the device ispositioned in the tooth. As seen, the filler material 54 is mounted tothe distal end or bed portion 52 b of the shaft, and the bed portion 52b extends along the exterior of the of filler material 54 (e.g., acone/plug) the full length of the cone/plug 54, such that at least aportion of the bed portion 52 b is exposed. Preferably, the end of thebed portion 52 b is generally even with the end or apex or distal end 54a of the filler material 54. As seen in FIG. 3B, the bed portion 52 b isembedded into the side of the filler material 54 such that aboutone-half the diameter of the bed portion 52 b extends from the side ofthe filler material 54. As such, when the delivery device is inserted ina root canal, the shaft will be substantially against the wall of theroot canal, rather than in the center of the root canal. This will allowfor the introduction of a plugger, as just noted above, to allow thepractitioner to at least start molding the filler material while thedelivery device is still in the root canal.

As seen in FIG. 3A, the stem portion 52 a can be bent as at 52 d todefine an upper short portion 52 c which is concentric with theconnecting portion 50 and angled relative to a main or lower part of thestem portion 52 a. The angle 52 d is sized to facilitate insertion ofthe delivery device into a root canal by a practitioner. If desired, theshaft 52 (and thus the stem portion 52 a) could be provided straight. Ifstraight, the shaft 52 could be bendable so that the practitioner couldform the shaft to a desired configuration. The shaft 52 is, at least atits distal end, sufficiently thin, so that the end of the shaft 52 canreach to the apex of the root canal with the filler material (e.g.,cone/plug) adhered thereto. Additionally, root canals are not typicallystraight. Thus, the shaft 52 is made from a material that issufficiently flexible to enable the shaft to navigate turns and curvesin 3 dimensions in the root canal, while at the same time, to besufficiently rigid to support the filler material 54 so that thepractitioner can insert the filler material 54 into a prepared toothroot canal while grasping the delivery device connecting portion 50.

A temperature sensor 56 (FIG. 3C), such as a thermocouple, thermistor,micro temperature probe, micro-chip sensor, etc., can be mounted to thebed portion 52 b rearwardly of the apex 54 a of the filler material 54to provide an indication of the temperature of the bed portion 52 b andof the filler material proximate the apex of the filler material 54.Importantly, the temperature sensor 56 is in thermal communication withthe filler material 54 so that the temperature sensor will transmit asignal indicative of the temperature of the filler material. Forexample, the temperature sensor can be positioned about 3 mm (about0.1″) above the apex of the filler material 54. Although this wouldallow for a very precise measurement of the apical temperature,temperature sensors could be placed in other areas of the deliverysystem and allow for similar high level calibrations of the apicaltemperatures. Temperature sensors other than those disclosed above andwhich can be made small enough to fit into a root canal can be used aswell.

As will be discussed in more detail below, the obturation system 10 isdesigned to better control the placement of the filler material inrelation to the end of the root at the time of obturation as well asdirectly establish and control temperature delivery to the apical fillermaterial. This will establish better molding parameters in deep levelsof the root canal system and therefore allow for a better seal of thedistal or apical end of the root canal. However, because canals are ofvarying length, this system may seal the entire canal in some cases.This would occur, for example in shorter canals. Therefore, in additionto better controlling the parameters in the apical ⅓ of the root canal,the system could be utilized to seal an entire canal. In an alternativeembodiment, the system could also fill the remaining canal directlyafter or upon the sealing the apical end if the holder was also equippedwith a filler material extrusion device. Such filler material extrusiondevices are common, but are typically only used after the apical end ofa root canal is sealed, as discussed above.

The filler material 54 is about 4 mm-12 mm long, preferably about 8-10mm (about 0.3″) long, as supplied and will be provided in varioussizes/tapers. In other dental and non-dental embodiments, the fillermaterial may be smaller or significantly larger. In some embodiments,the apical size of the filler material will be designed to match themain shape of the prepared canal (or other desired target site, whetherin dental or non-dental tissue cavities). Said differently, the fillermaterial will be made to match the size/taper of various files used toprepare the canal or other desired location, and the filler materialwill be provided in different sizes to facilitate matching the fillermaterial to the shape of the prepared canal.

The connecting portion 50 of the delivery device will be about 8-12 mmlong in one embodiment. The shaft 52 can vary in length to allow forvarious overall lengths corresponding to the various lengths ofindividual canals. Therefore, the length of various the sizes ofdelivery devices 16 will vary mainly in the length of the shaft 52. Theoverall length of the various sizes of the delivery device 16 will be ina range of 20-45 mm. The shaft 52 is, at least at its distal end,sufficiently thin, so that the end of the shaft 52 can reach to the apexof the root canal with the filler material cone/plug mounted thereto.Additionally, root canals are not typically straight. Thus, the shaft 52is made from a material (including, but not limited to platinum, silver,gold, copper, aluminum and alloys thereof or other thermally conductiveand/or electrically conductive metals or alloys) that is sufficientlyflexible to enable the shaft to navigate turns and curves in 3dimensions in the root canal, while at the same time, to be sufficientlyrigid to support the filler material 54 so that the practitioner caninsert the filler material 54 into a prepared tooth root canal whilegrasping the delivery device connecting portion 50. Further, the shaftcould be made from a composite which is coated with, platinum, silver,gold, copper, aluminum and alloys thereof or other thermally conductiveand/or electrically conductive metals or alloys. In this manner, thedevice may be particularly beneficial for non-dental applications withtortuous pathways. The connecting portion 50 can be made in manyconfigurations. For instance, the connecting portion 50 could be hollow,to define a path through which a plugger can extend. Ultimately, theconfiguration of the connecting portion 50 will allow for propercompletion of circuitry discussed herein, a good connection for heattransfer, and for securing the delivery device 16 to the holder forwithdrawal from the root canal.

A schematic for the obturating system according to one embodiment isshown in FIG. 5. As seen therein, the system includes a main controller60, an apex locating circuit 62 and a heating circuit 64, all of whichare in the holder 14. The apex locating circuit 62 includes the deliverydevice 16, the lip clip 48, and a resistance/impedance monitoringcircuit 66 (FIG. 6A). At least the outer or exposed surface of the bedportion 52 a (which will contact the wall of the root canal wheninserted into a prepared root canal) is made from, or is coated with, anelectrically conductive metal or alloy. For example, the surface of thebed portion 52 a (and of the shaft 52 has a hole) can be made from, orcoated with, a NiChrome alloy, or silver or a silver alloy. The shaft 52of the delivery device 16 is placed in electrical communication with theresistance monitoring circuit 66 by way of the connecting portion 50 ofthe delivery device 16 through the fingers 42 b of the holder arms 44.As noted above, the shaft bed portion 52 b extends the full length ofthe filler material cone/plug 54 and is positioned along the side of thefiller material cone/plug 54. When the shaft 52 with the filler materialcone/plug 54 is inserted in a prepared root canal, the shaft 52 willcontact the surface of the root canal. As is known, the resistance ofthe apex locating circuit 62 varies as the end of the shaft approachesthe end of the root canal (e.g., as the shaft 52, and hence the fillercone/plug 54, are inserted further into the root canal). Stateddifferently, the position of the end of the shaft 52, and therefore thefiller plug 54 in a root canal can be determined by the measured ordetermined resistance/impedance of the apex locating circuit 62.

As noted above, the shaft 52 may be placed in electrical communicationwith the resistance monitoring circuit 66 of the apex locating circuit62 by way of the delivery device connecting portion 50 and the holderarms 42. The holder arms 42 (or the surfaces thereof) can themselves beconductive, or an electrical conduit can extend along or through thearms 42 a to the fingers 42 b. The electrical conduit can be defined bya wire which extends along (or through) the arms 42 a to the fingers 42b or by a printed trace which extends along (or through) the arms 42 ato the fingers 42 b. At least the inner surface 42 c of the fingers 42 bare electrically conductive.

The connecting portion 50 of the delivery device 16 can be made of ametal or metal alloy, or other material. Alternatively, the connectingportion 50 can define an electrical path which extends from the surfaceof the connecting portion 50 to the shaft 52. Thus, when thepractitioner holds a delivery device 16 between the fingers 42 b of theholder 14, as shown in FIG. 4, the shaft 52 will be placed in electricalcommunication with the resistance monitoring circuit 66 of the apexlocating circuit 62. The resistance monitoring circuit produces a signalindicative of the depth or location of the end of the shaft 52 (e.g.,location information), based on the varying resistance of the apexlocating circuit 62 as the shaft 52 of the delivery device 16 isinserted into the canal. Hence, the signal from the resistancemonitoring circuit 66 is indicative of the location of the apex or endof the filler cone/plug 54 relative to the working end or apical foramenof the prepared root canal. This signal is received by the maincontroller 60 in the holder 14 and transmitted to the controller 36 inthe base 12. This signal can be transmitted either wirelessly or througha wire which extends between the holder 14 and the base unit 12.Alternatively, the signal can be sent directly to the controller 36 ofthe base 12 (in which case, the holder would not have a controller). Thecontroller 36 in the base unit 12 then drives the display 30 toillustratively show the practitioner on the scale 34 of the display 30where in the root canal the end of the shaft and the apex or end of thefiller cone/plug are located, as the delivery device is inserted intothe canal. As can be appreciated, the system 10 informs the practitionerof the location of the plug in the root canal.

In one embodiment, the scale 34 is comprised of a plurality of segmentsof varying colors. Illustratively, the colors can vary from red toyellow to green. In one illustrative embodiment, the segments at thebottom of the scale 34 are green, and in particular, the bottom segment34 a is of a different green than the segment or two immediately abovethe bottom segment 34 a. When this bottom segment 34 a is lit, thepractitioner will know that the bottom of the shaft 52 and the apex ofthe cone/plug 54 are at the apex of the root canal, or just shy of theapex of the root canal (e.g., within about ½ mm-¼ mm from the apex ofthe root canal). The practitioner can then compare this reading with thetactile fit of the filler material. When the bottom segment 34 a of thescale 34 is lit, as will be discussed more fully below, it is safe tooperate the heating circuit 64 to seal the apex of the root canal.Although a graph or bar chart 34 is used in the display 30 to inform thepractitioner of the location of the end of the shaft 52 in the rootcanal, the display 34 could take on many other forms. The display could,for example, be a needle graph (such as a typical speedometer).Alternatively, the display could simply be a numeric display, whichshows depth in millimeters, for example. In addition, the system canprovide an audible signal when the end of the shaft 52 is at the apex ofthe root canal. Further, audible signals can be provided when the shaft52 extends too far (e.g., is in danger of extending through, or doesextend through, the apical foramen of the root canal) and/or is stillshy of the root canal apex. If audible signals are provided, the soundindicating that the filler material is in an acceptable location will bedifferent from the sound indicating that the delivery device has beenextended through the apical foramen of the root canal. Such audiblesignals can be provided by a speaker (or other sound generator) providedon either the holder 14 or the base unit 12. Alternatively, or inaddition, the holder can provide a tactile feedback (in the form ofvibrations) to inform the practitioner when the distal end of the shaft(and hence the filler material) is properly positioned in the root canalor if the shaft has extended through the apical foramen into tissuesurrounding the tooth root. As with the audible signals, the tactilesignal for an acceptable (or “go”) position in the canal will bedifferent from the tactile signal for a “no-go” position in the canal.If a sound generator is provided, it would be activated by either thebase unit controller 36 or the holder controller 60, depending on wherethe sound generator is located. The tactile feedback would be activatedby the holder controller 60.

The heating circuit 64 (FIG. 6B), according to one embodiment, includesa heating device or element (not shown in the drawings) and the switch46. The heating device is activated by pressing on the switch 46. Theactivation of the heating device can be automatically controlled by themain controller 60 in response to the signal from the apex locatingcircuit 62. Accordingly, if the controller 60 determines that the end ofthe shaft 52 is not at the apex of the root canal (e.g., is either stillshy of an appropriate distance from the end of the root canal or has isextended through the apical foramen of the root canal), the controller60 will not allow the heating circuit to be activated. Thus, thecontroller 60 will allow the heating circuit to be activated (or willactivate the heating circuit) only when the end of the shaft 52 iswithin a predetermined range at the apex of the root canal. If thedelivery device is determined to extend beyond or through the apicalforamen of the root canal, the controller 60 can activate a visualand/or audible warning device informing the practitioner of that fact.In this more automatic system, wherein the controller activates theheating circuit, the switch 46 would be an activation switch for thecontrol system.

In one embodiment, the heating device can be located in the handpiecebody 40, in which case, the heat is conducted through the arms 42 to thedelivery device connecting portion 50 and then to the shaft 52 of thedelivery device 16. Alternatively, the heating device can be located inthe fingers or grips 42 b or the holder arms 42. As another alternative,the heating device can be located in the connecting portion of thedelivery device. Finally, the heating device can be located in bedportion of the delivery device, in which case, the heating device willbe adjacent the filler material. The heating device can be of severaldifferent types, depending on where it is located. If the heating deviceis located in the body of the handpiece or in the delivery deviceconnecting portion, the heating device can be, for example, an inductiveheater which utilizes an electrical coil, a piezoelectric heatingdevice, a magnetic heating device, or a resistance wire. If the heatingdevice is located in the grips 42 b of the holder arms, or the shaft ofthe delivery device, the heating device is preferably a resistance wireor circuit that could extend down the delivery device. It will beappreciated that the heating device can be any heating device and itcould be positioned at various levels of the delivery system. Therefore,the location and the type of heating device are not limited by the listjust set forth.

In one embodiment, the filler material 54 is heated along its entirelength (or along substantially its entire length) and is heated from itsside (and is thus heated transversely). This allows for heat to beapplied directly to the filler material substantially along the lengthof the filler material, as opposed to a method of attempting to heat thefiller material longitudinally from the top (or coronal-most end) of thefiller material. Because the filler material 54 is being heated from itsside, and along substantially the entire length of the filler material54, the high temperatures used by current devices are not necessary forthe filler material to be heated to the point where substantially theentire plug of filler material becomes moldable. Further, the fillermaterial is relatively small in diameter in one embodiment. Althoughgutta-percha (the most commonly used filler material in obturation) is apoor conductor of heat, with the short distance the heat must travel (atits widest, in one embodiment, the filler material is about 0.4 mm toabout 2 mm in diameter at its upper end and about 0.1 mm-0.5 mm at itsapex), the heat will be conducted through the gutta-percha relativelyquickly, and the entire gutta-percha cone/plug will be substantially ata uniform temperature. That is, in several embodiments, there will be nosubstantial temperature gradients, either from side-to-side or fromtop-to-bottom in the filler material (e.g., the gutta-percha cone/plug)54. In some embodiments, the vertical and/or horizontal temperaturegradient will vary by up to about 5° C., up to 10° C., up to 15° C., upto 20° C., and up to 25° C., etc. For example, the top part of thefiller material in one embodiment will be about 50° C.-60° C., theapical most part may be about 40° C.-45° C. The consistency oftemperature is advantageous in several embodiments because itfacilitates more even and consistent heating and molding. Further,tighter temperature ranges from the proximal to the distal ends of thefiller material permit a lower temperature to be delivered, whichincreases safety and may allow for enhanced precision.

Gutta-percha has been shown to be moldable at temperatures as low as 39°C.-40° C. (about 102° F.-104° F.), and changes from its β phase to its αphase around 42° C.-49° C., depending on the filler materials used inthe particular gutta-percha formulation. In several embodiments, theheating circuit will heat the filler material (e.g., gutta-perchacone/plug) to between about 37° C. and about 65° C., (e.g., about 42°C.-50° C. in one embodiment, and between around 42° C.-46° C. in anotherembodiment). When gutta-percha formulations and manufacture processesare controlled, the temperature mediated phase transitions should be ina known range. The ability of this system, in several embodiments, todirectly delivery heat will allow for a better control of temperaturedelivery. This will allow for the system to be programmed in a way toattempt to avoid the temperature mediated phase transitions and henceavoid complication related to shrinkage

According to some embodiments, the temperature sensor 56, which islocated on the bed portion 52 b of the delivery device 16, is placed incommunication with the controller 60 via the electrical conductivity ofthe shaft 52 and connecting portion 50, as noted above; and the signalsfrom the temperature sensor 56 are received by the main controller 60 inthe holder 14. The controller 60 will control the holder display 44 todisplay the temperature of the filler material. This information can berelayed to the base unit controller 36 to show the temperature on thebase display 30. In one variation, the holder can be made without adisplay, and the temperature of the filler would be displayed on thebase unit display 30.

In some embodiments, an optional holder is provided. In one embodiment,the holder controller 60 will control the heating circuit 64 and itsassociated heating element in response to signal received from thetemperature sensor 56 to heat the filler material to the desiredtemperature. The system can be provided with a timer 68. The timer canbe activated either when the heating circuit is activated, or when thecontroller determines the filler material is at the desired temperature.For example, if the filler material is gutta-percha, it need only beheated for not more than about 10 seconds, and preferably about 2-5seconds. After the desired temperature has been achieved for aprogrammed time period, the controller will deactivate the heatingcircuit. During the heating cycle, the controller will control theheating circuit based on the continuing signals received from thetemperature sensor so that the temperature of the filler material willbe accurately and precisely controlled. The controller can also give anaudible and/or visible and/or tactile indication that the heating cycleis over. Thus, the filler material will be precisely heated to a desiredtemperature and for a desired period of time. When the practitionerreceives the signal that the temperature parameters have been reachedhe/she can manually remove the delivery device (or the delivery devicecan be automatically withdrawn, as discussed in an alternativeembodiment below). The end of the heating cycle will occur once theshaft 52 has been removed from the canal, leaving the filler material inthe canal. Because the shaft 52 of the delivery device 16, andparticularly the distal end 52 b of the shaft, are along the side of thefiller material and adjacent the canal wall, a plugger can be used tonot only ensure that the position of the filler material is notadversely affected as the shaft 52 is removed but also to allow forsimultaneous molding as the filler material is being heated. When theshaft is removed, the source of heat will also be removed.

During an endodontic procedure, use of the obturation system 10 beginsafter a canal has been shaped, cleaned/disinfected and dried. To use thesystem 10 according to one embodiment, the practitioner will select adelivery device 16 and grasp it with his/her fingers or an instrument,such as with pliers or forceps or the holder 14. Again, as can beappreciated, because canals are of different tapers and diameters, thedelivery device 16 will be selected such that the filler material 54corresponds with the final files used to shape the canal. Thepractitioner will insert the selected delivery device 16 with the fillermaterial 54 into the canal, and trim and fit the filler material 54, asis generally done currently, so that the filler material 54 will have agood fit in the apical portion of the root canal. However, unique tothis system in several embodiments, the practitioner will be ableutilize apex locator technology to compare this tactile feeling to theposition of the filler material as determined by the system 10. In thiscase, the practitioner compares the reading of the apex locator to thesensation perceived when the practitioner fits the delivery device. Fromthe feeling of a “tug back” while fitting the filler material 54 in thecanal at the determined canal length (e.g., pulling back from the cone'smost downward position), the practitioner can be fairly certain that thefiller material (e.g., cone/plug) has a good apical fit. In oneembodiment, if the temperature sensor is provided on the delivery device16, the temperature sensor can be positioned proximal to the apex of thefiller material (e.g., about 3 mm from the apex). This allows thepractitioner to trim up to about 3 mm from the end of the fillermaterial and without affecting the temperature sensor. Although thetemperature sensor is disclosed as being 3 mm from the apex of thefiller material 54, the distance of the temperature sensor from the apexof the filler material 54 can be varied. In several embodiments, thetemperature sensor 56 can be spaced from the apex/end of the fillermaterial 54 a distance sufficient to allow a practitioner to trim thefiller material without cutting the temperature sensor from the deliverydevice 16. In one embodiment, to facilitate precise heating of thefiller material 54, the position of the temperature sensor relative tothe filler material can be accounted for in the controller for theheating circuit.

When the filler material 54 has been trimmed and fitted, thepractitioner will withdraw the delivery device 16 with the fillermaterial 54 from the root canal, apply a sealer to the filler material54 and reinsert the delivery device 16 into the root canal. Thepractitioner will then grasp the delivery device at the delivery deviceconnector portion 50 with the holder arms 42, as shown in FIG. 4.Alternatively, the practitioner can grasp the delivery device 16 withthe holder 14, and use the holder 14 to insert the delivery device intothe root canal. In one embodiment, the practitioner grasps the deliverydevice with the holder (similar to pliers), and then holds the deliverydevice (similar to a dagger) with the holder to insert the deliverydevice into the canal. When the arms 42 grasp the delivery deviceconnector portion 50, the delivery device becomes part of the apexlocating circuit, and the controller can confirm that the apex of thefiller material (e.g., cone/plug) is in the correct position, e.g.,within about ¼ mm-½ mm of the apical foramen of the root canal. Theposition of the apex of the filler material will be displayed on thedisplay 30. If it is determined that the apex of the filler material isin the proper position in the root canal, the holder controller 60 willallow the heating circuit to be activated. The practitioner activatesthe heating circuit by pressing the switch 46. If the practitionerpresses the switch 46 when the delivery device is not in an acceptableposition in the root canal, as determined by the controller based uponfeedback from the apex locating circuit, the controller will notactivate the heating circuit 64. Although the switch 46 is disclosed tobe on the arms 42 of the holder 14, the switch could be locatedelsewhere on the holder, or even on the base unit 12.

Activation of the heating circuit will directly deliver heat to thefiller material 54 along the length of the filler material, as describedabove. The holder controller 60 will monitor the temperature of thefiller material (in this example, gutta-percha) by means of the signalsfrom the temperature sensor. When the controller 60 determines that thegutta-percha has reached a desired temperature, the controller willstart the timer 68, and based on the output from the temperature sensor,will maintain the gutta-percha at the set temperature for apredetermined period of time (about 2-10 seconds), as noted above. Whenthe heating period has ended, the controller 60 will prompt thepractitioner to remove the shaft 52 of the delivery device and willdeactivate the heating circuit. This prompt can be in the form of anaudible and/or visible and/or tactile prompt.

In several embodiments, the shaft 52 extends along the side of thefiller material (e.g., cone/plug) 54, rather than through the center ofthe filler material. The shaft 52 thus will not be in the way of placinga plugger in the root canal while the shaft is in the canal. In oneembodiment, the plugger can be placed in the canal during heating (e.g.,before the heating cycle is initiated). The system can include either avisual or audible indicator to let the practitioner know that the fillermaterial is at its molding temperature, and that the practitioner canthus begin molding of the filler material by pressing on the fillermaterial with the plugger. This will allow for molding of thegutta-percha (in this example) in the canal during heating.Additionally, by pressing on the filler material 54 while the bed 52 bis being removed from the heated gutta-percha and the canal thepossibility that the position of the filler material left in the canalwill be adversely affected during removal of the shaft 52 from the canalis reduced. Due to the mechanical properties of the gutta-percha at itsmolding temperature, the gutta-percha will not adhere too tightly to theshaft bed portion 52 b, and the shaft 52 can be separated from thegutta-percha fairly easily without materially affecting the position ofthe gutta-percha in the root canal. To facilitate the removal of theshaft 52 from the canal, the shaft can be provided with a release agentwhich is activated at the temperature to which the filler material 54 isheated. The release agent can be a material which has adhesiveproperties when cool (to help secure the filler material 54 to the shaftbed portion 52 b) and which loses its adhesive properties upon heatingto allow for the shaft 52 to be slipped from the filler material 54.

In some embodiments, the filler material 54 is about 8-10 mm in lengthand shaped as a cone. Other dimensions and shapes may also be used fordental and non-dental applications (e.g., cylindrical, triangular,rectangular, etc.). In one embodiment, once the filler material 54 istrimmed to fit into the canal, the filler material will be about 5-10 mmin length. When the heated filler material 54 is pressed using theplugger, the filler material will be molded to three-dimensionally fillthe apical end of the root canal in an attempt to seal most, if not allaspects of the apical end of the root canal. In one embodiment, the 5-10mm long filler material will thus seal and fill approximately 3-8 mm ofthe apical end of the root canal.

Further, because the gutta-percha is not heated substantially above 65°C. in several embodiments, the gutta-percha filler material will not beheated substantially above its higher temperature mediated amorphousphase change melting temperature. The high temperatures used bycurrently available heating devices can lead to shrinkage as thegutta-percha cools. Further, depending on the type of gutta-percha usedand the temperature parameters programmed within this system, thegutta-percha can be heated for molding, yet heated below its lower betato alpha phase transition temperature (about 42° C.-49° C.). This wouldnot only allow for decreased chances of potential shrinkage, it has beenshown that this can result in an overall expansion of gutta-percha byabout 1%. Although a very small amount, this would be advantageous fordensely sealing the canal in three-dimensions. Moreover, thiscontrolled, direct delivery of lower heat as compared to other systemswhich heat the gutta-percha substantially above these temperaturemediated phase transition temperatures is very advantageous. Stateddifferently, the shrinkage that occurs with the high heat systems willbe reduced or even avoided according to several embodiments of theinvention.

The obturation system 10, when used according to several embodimentsdescribed herein, will densely and three-dimensionally seal at least thebottom ⅓ of a prepared root canal. The proper sealing of the apex isvital to a successful endodontic procedure. This method allows for abetter seal of the apex of the root canal, by not introducing high heatinto the root canal, as is required using currently available heatinginstruments. As noted above, the gutta-percha cone/plug is heated along,or substantially along, it's full length (e.g., to the apex of thefiller material), to allow substantially the full extent of the fillermaterial (e.g., gutta-percha cone/plug) to be heated, and heatedgenerally evenly. Thus, several embodiments of the invention provide forsmaller temperature ranges along the filler material. In one embodiment,this more even heating of the filler material, along with the fact thatthe filler material is not heated substantially above its phase changetemperature, will allow for a better and tighter seal of the apical endof the root canal. Once the root canal is sealed, the remainder of thecanal can be filled with gutta-percha or other filler material in aconventional manner. That is, the remainder of the root canal can befilled via a hot vertical, cold vertical, or cold lateral method.Alternatively, the remainder of the root canal can be filled usingheated filler which is extruded into the canal (e.g., like hot glue).Additionally, although not shown, the system disclosed herein could alsoemploy an extrusion component to allow for the delivery of additionalfiller material at the time of or directly after the apical plug 54 hasbeen activated (heated), and the shaft 52 has been withdrawn.

In a variation of the system 10, the switch 46 can be eliminated. Inthis variation, when the controller determines that the apex or distalend of the filler material is in the proper position in the root canal,the controller 60 will automatically start the heating cycle. Such asystem could, however, include an activation switch (such as an on/offswitch) to activate the system. In addition, the system can include thetimer, and the controller can then automatically stop the heating cyclewhen the filler material has been heated to its desired temperature fora predetermined period of time (e.g., 2-10 seconds) and the shaft hasbeen removed.

An alternative embodiment of the obturation system 110 is shown in FIGS.7A-E The obturation system 110 includes a base unit 112, a holder 114, afiller material delivery device 116, a plugger 117, and a lip clip 148.In the obturation system 110, the holder 114 removably receives thedelivery device 116 (albeit in a different manner than the holder 14receives the delivery device 16), and the holder 114, the plugger 117and the lip clip 148 are all connected to the base unit 112 by way ofelectrical cables 170, 171 and 172. In the obturation system 110, thecomponents for the control system 180 (FIG. 30) are contained largely inthe base unit 112, and the cables 170-172 place the holder (and hencethe delivery device 116), the plugger, and the lip clip 148 inelectrical communication with the control system 180. The communicationbetween and among the components of the system 110 allows for precisecontrolling of the heating of the filler material delivered to theapical end of the root canal.

In several embodiments, the base unit 112 (shown generally in FIGS.7A-E) includes a body housing 112 a having a top surface 126, sidesurfaces 122, front surface 124, a back surface and a bottom. The baseunit 112 is shown to be generally triangular in side elevation with thefront surface 124 forming a curved connection between the top surface126 and the bottom. The base unit 112 can have any desired shape orconfiguration. Externally, the base unit includes a display 130, controlbuttons 132 and a power or activation button 134. The cord 170 extendsfrom one side 122 of the base unit 112 to electrically connect theholder 114 to the base unit and to place the holder 114 in communicationwith the base unit. In addition, second and third cords 171 and 172(only cord 172 is shown) extend from the base unit to electricallyconnect the lip clip 148 and plugger 117 to the base unit 112. The cords170-172 place the holder, the plugger and the lip clip in electricalcommunication with the controller in the base unit 112. If either theholder 114 or plugger 117 communicates with the base unit wirelessly,then their respective cords can be omitted. If the plugger 117 is notprovided with a temperature sensor (in which case the temperature sensorwould be located on the delivery device 116), then plugger need not beplaced in communication with the base unit 112, and its cord can beomitted. The lip clip 148 and delivery device 114 are both part of theapex locating circuit 186. The lip clip could be connected directly tothe holder 114, in which case, the holder could communicate wirelesslywith the base unit. However, if the lip clip is directly connected tothe base unit, there will need to be a corded connection between theholder 114 and the base unit 112, so that the apex locating circuit willbe complete.

In one embodiment, the display 130, like the display 30, includes aportion that displays the temperature of the filler material (e.g.,cone/plug) and an image of a root canal to graphically display where inthe canal the delivery device, and hence the filler material, islocated. The control buttons 132 can be used to adjust the settemperature (e.g., the temperature to which the filler material isprogrammed to be directly heated). The control buttons 132 can also beused to adjust the duration of the heating cycle.

One example of the delivery device 116 is shown in FIGS. 8A-9D. Thedelivery device 116, like the delivery device 16, includes a cylindricalbody, grip or connecting portion 150 which is sized to be grasped by apractitioner. Again, this connecting portion 150 can take on anyconfiguration. Ultimately the configuration of the connecting portion150 will allow for proper completion of circuitry discussed herein, andsecuring the delivery device for withdrawal from the canal. In addition,this connection may be used for heat transfer, and in this case theconfiguration of the connecting portion 150 would allow for a goodconnection for heat transfer. In this embodiment, the shaft 152 is inthe form of a strip of heat conductive material, which is shown to becurved or arced along its length. This strip of material will besufficiently thin and flexible so that the shaft will be able tonavigate curves in the root canal to reach to the apical end of the rootcanal, yet be sufficiently rigid to drive the filler material to theapical end of the root canal. In this embodiment, because the shaft 152is in the form of a curved or arced strip, the shaft 152 willeffectively blanket or wrap around a portion of the side surface of thefiller material 154, as best seen in FIG. 9A. This will allow the heatthat is transmitted to (or generated on or in) the shaft bed portion 152b to be applied to a greater surface area of the filler material 154.This will lead to more even heating of the filler material. In addition,the thin strip of the shaft material will occupy a small amount of spacewhich will need to be filled in with molded/packed filler material uponremoval of the shaft from the root canal. As best seen in FIGS. 9A and9B, the shaft bed 152 b to which the filler material 154 is mounted iscurved and tapered, with the curvature and taper generally matching thecurvature and taper of the filler material, as seen in FIGS. 8B and 9A.The filler material 154 can be adhered (e.g., molded) to the bed portion152 b of the shaft 152 such that the outer surface of the shaft 152 isgenerally flush with the outer surface of the filler material 154, toprovide a generally smooth transition between the filler material of thefiller material and the shaft, as shown in FIG. 9A. Because the shaft152 extends to the apex of the filler material 154, the bed portion 152b of the shaft which overlays the filler material 154 has diagonal edgeswhich meet, such that the shaft 152 comes to a point at its distal end152 a (e.g., the end remote from the body 150).

In the delivery device 116, according to one embodiment, a temperaturesensor 156 (FIG. 9D) can be secured to, or could even be embedded in,the shaft bed portion 152 b. Leads 156 a (FIG. 9A) for the temperaturesensor 156 can extend along, or be embedded in, the shaft 152. Heat canbe delivered to the filler material 154 through the shaft 152 in thesame manner as discussed above with the shaft 52. That is, the heatingdevice is located in the holder 114, in the delivery device grip 150 orin the shaft bed portion 152 b. As with the delivery device 16, becausethe shaft bed portion 152 b extends along, or substantially along, thefull length of the filler material 154 in some embodiments, the heattransmitted by or through the shaft bed portion is delivered directly tothe filler material 154 along the length of the filler material 154. Ifa heating element is positioned at the level of the filler material(e.g. if the heating element is located in or on the shaft bed portion152 b), the leads 157 for the heating element can extend along (or beembedded in) the shaft 152. As seen in FIG. 9C, the leads 156 a and 157for the temperature sensor 156 and the heating device, respectively,extend into the body or grip 150 of the delivery device 116.Additionally, the wires/leads for the temperature sensor 156 may servethe additional purpose(s) of delivering a heating current to the shaftand/or serving as the effective probe (the varying resistance of whichis measured) by the apex locating circuitry to determine when the end ofthe shaft is at the apex of the root canal.

In one embodiment, to facilitate the apex locating function of thedelivery device 116, the shaft 152, itself, can be electricallyconductive (in which case, the shaft itself will form the probe of thelocating circuit, as with the shaft 52 of the delivery device 16).Alternatively, the varying resistance of the leads 156 a for thetemperature sensor 156 can be monitored to confirm that the apex of thefiller material 154 is at the apical end of the canal. This wouldrequire that the leads be exposed along the outer surface of the shaft152 so that the leads could contact the wall of the prepared root canalduring use. If the temperature sensor leads 156 a are used as part ofthe apex locating circuit, the controller system 180 would alternativelyswitch between monitoring the temperature output data of the temperaturesensor 156 and monitoring the resistance of the leads 156 a, so that thecontroller can then monitor both the temperature of the filler materialand the location of the apex of the filler material 154 and the end ofthe material strip 152 and then control the heating circuit based on theinformation from the apex locating circuit and the temperature sensor.Alternatively, because the shaft 152 in strip form presents a largersurface area than the shaft 52, if the shaft 152 (or at least its outersurface) is not electrically conductive (and thus does not itself definethe apex locating probe), an electrically conductive strip can beprovided which extends along the outer surface of the shaft. Such aconductive strip can be in the form of a wire adhered to the outersurface of the shaft 152 or as a printed trace or track on the outersurface of the shaft 152. In this instance, this conductive strip willdefine the probe for the locating circuit.

An alternate delivery device 116′ is shown in generally in FIGS. 10A-B.The delivery device 116′ includes an upper connecting portion 112′ whichcontains a locking means 114′ for removably connecting the deliverydevice 116′ to a holder or heating chamber. This locking means (which isnot shown in FIG. 10B) can include a spring biased member which engagesa dimple in the holder or a pin which engages a bayonet slot (as shownin FIGS. 15-16). In the drawings, the spring biased member is shown onthe delivery device, however, it could be contained in the holder.Similarly, the bayonet slot could be formed in the holder, and thedelivery device connecting portion could be provided with a pin whichengages the slot.

As seen in FIG. 10B, the connecting portion 112′ can define a tube. Theconnecting portion 112′ is shown to be generally cylindrical in FIG.10A, and to be flared slightly at its top in FIG. 10B. The holder can bea currently available holder, such as System B (available from SybronDental Specialties, Inc. of Orange, Calif.), Touch-n-Heat™ (availablefrom Sybron Dental Specialties), DownPack (available from Hu Friedy),Calamus Pack (available from Dentsply International), and Hot Tip(available from Discus Dental). Alternatively, the holder can be theholder 14 (FIGS. 2 and 4) or a holder such as is shown in FIGS. 16 and17, and which is described below. Other holders described herein mayalso be used. The upper connecting portion 112′ is illustratively shownto define an elongate cylinder which is open at both its opposite ends.However, this connecting portion can have other shapes andconfigurations if desired. A shaft portion 118′ extends from the bottomof the connecting portion. The shaft portion 118′ is shown to be arced,but could be formed to have other shapes. A bed portion 118 b′ isdefined at the distal end of the shaft portion 118′. The portion 118 a′of the shaft 118′ between the bed portion 118 b′ and the connectingportion 112′ defines a stem portion. The bed portion 118 b′ has an innersurface 119 a, an outer surface 119 b, and edges 119 c. The innersurface 119 a, as described below, is adapted to receive a plug offiller material 120 and to retain the filler material until the fillermaterial is heated, at which point, the filler material will be releasedfrom the bed portion 118 b′ of the delivery device 116′ to allow for3-dimensional molding of the filler material to fill and seal at leastthe apical end of the root canal.

In some embodiments, the bed portion 118 b′ is generally triangular inelevation, as seen in FIG. 12, and thus the side edges 119 c areinwardly sloping and define an apex 119 d at the bottom of the bedportion 118 b′ (and the bottom of the delivery device 116′). Further,the bed portion 118 b′ may not be co-linear with the shaft portion 118a′. Rather, the bed portion 118 b′ may define a slight angle withrespect to the shaft portion 118 a′, such that the apex 119 d isgenerally coaxially aligned with the cylinder of the connecting portion112′, as seen in FIG. 10A. Stated differently, the outer surface 119 bof the bed portion 118 b′ is tapered to correspond generally to thetaper of the plug of filler material. The delivery device 116′ can beformed in different sizes and with different tapers to accommodatedifferently sized root canals. The taper of the bed portion cancorrespond to the taper of the instrument/file used by the practitionerin preparing the canal. Preferably, the filler material 120 is mountedto the bed portion 118 b′ such that the bed portion and filler material,in combination, define a diameter and taper that corresponds to thediameter and taper of the finishing file used in preparation of thecanal.

As best seen in FIGS. 11 and 14A-B, the bed portion 118 b′ defines anarc in horizontal cross-section. The arc can be up to about 180° (e.g.,being generally semi-circular in cross-section). The curvature or arc ofthe bed portion 118 b′ corresponds generally to the curvature or arc ofthe shaft portion 118 a′ and to the curvature or arc of the fillermaterial 120. Hence, there is a generally smooth transition between thesurface of the bed portion and the surface of the filler material, suchthat the filler material and bed portion generally define a circle inhorizontal cross-section, as illustrated in FIG. 14B Further, the widthof the bed portion 118 b′ between the inner surface 119 a and outersurface 119 b varies along the length of the bed portion. The bedportion 118 b′ is thickest at the top of the bed portion (proximate theshaft portion 118 a′), where the bed portion can have a thickness of 0.1mm, for example, and is thinnest at the apex 119 d where the bed portioncan have a thickness of 0.05 mm, for example. Additionally, the fillermaterial 120 is positioned on the bed portion 118 b′, such that the apexof the filler material 120 is proximate the apex 119 d of the bedportion 118 b′. That is, the apex of the bed portion is at or within afew millimeters of the apex of the filler material.

In accordance with one aspect, the bed portion 118 b′ is provided withat least one retentive feature to enable the bed portion 118 b′ to helpphysically retain the filler material 120 on the bed portion until thefiller material is activated (e.g., heated) in a root canal to bereleased or separated from the delivery device bed portion 118 b′ formolding of the filler material in the root canal. The retentive featurescan take several forms. The bed portion 118 b′ can be provided with justone of the retentive features or any combination of two or more of theretentive features. Upon heating of the filler material duringobturation, the filler material softens and the delivery device 116′ canbe easily slipped from the plug 120 of filler material while the fillermaterial remains in the canal for 3-dimensional molding. This moldingprocess may be enhanced by a plugger, to allow for molding at the timeof (i.e., during) heat delivery and to help retain the filler materialin position during withdrawal of the delivery device 116′ from thecanal.

The retentive feature can include holes 122 which are formed in the bedportion. The holes 122 can be formed by punching them through the bed118 b′. In doing so, the flashing (not shown) formed by the punchingprocess can be left in place or removed, as may be desired. If theflashing from the punching operation is left in place, the flashing willform a retentive feature. Further, a rim (not shown) can be formedaround the hole. This rim can be a raised rim or an indented rim, andcan completely or only partially surround the hole. The holes 122 areshown to be circular, but could be any desired shape. For example, thehole could be a slot, and the slot could be provided with a rim at oneend of the slot. Additionally, the holes are shown to be of increasingdiameter from the end or apex of the bed portion 118 b′ towards theupper end of the bed portion 118 b′, however; the holes 122 could be ofconstant diameter. Further, although the holes are shown to be generallyaligned, the holes can be formed in any desired pattern.

The retentive feature can also be formed as cutouts or indents 124 inthe side edges 119 c of the bed portion 118 b′. The cutouts or indentsare shown to have a lower edge which is generally perpendicular to theside edge 119 c of the bed portion 118 b′, an upper edge which slopesdownwardly from the side edge 119 c, and an inner edge which isgenerally parallel to an axis of the bed portion 118 b′. Thus, thecutout/indent 124 defines a trapezoid with essentially three rightangles. Of course, the cutouts 124 could be of any desired shape. Forexample, the cutouts 124 could be arced, v-shaped, rectangular, etc. InFIG. 11, the bed portion is shown with only the holes 122; and in FIG.12, the bed portion is shown with both holes 122 and cutouts 124. As canbe appreciated, the bed portion can be formed with only cutouts 124.

As another example, the retentive feature can include the bed surface118 b′ being roughened. The bed inner surface 118 b′ can be roughened,for example, by etching or abrasive blasting to give the surface thetexture of, for example, sandpaper. In addition, the surface texturecould be accomplished through a plating process. Alternatively, theroughened surface can be defined by a pattern of lines, ridges, orshapes which are formed in the bed surface 118 b′. The lines of theretentive feature can be formed, for example, in a crisscross pattern.Such a pattern can be stamped into the bed surface or plated on the bedsurface.

As a further example, the retentive feature can include the side edges119 c of the bed 118 b′ being bent inwardly to form inwardly extendingflanges 125 (FIG. 14B). The flanges can extend substantially the lengthof the bed, or be defined by discrete elements or fingers (e.g., have aplurality of cutouts).

Additionally, the retentive feature can include an adhesive which isapplied to the bed and which will adhere to the filler material plug tothe bed. The adhesive can be an adhesive that when heated will lose itsadhesive properties which will enable the filler material plug 120 toseparate from the bed portion 118 b′.

In several embodiments, when the filler material 120 is applied to thedelivery device bed 118 b during manufacture or production of thedelivery device 116′, the filler material can be heated, molded andpressed/compacted against the bed inner surface 119 a. Conditions suchas heat, pressure and vacuum/suction will assist the filler material toengage the retentive feature(s) of the bed. Additional manufactureprocesses may allow for high levels of results in the application of thefiller material 120 to the delivery device bed 118 b′. This couldinclude the use of such things as solvents to soften the filler material120 for application to the delivery device bed 118 b′. For example, thefiller material can be dipped in a solvent (such as chloroform or orangesolvent). The solvent softens the gutta percha filler material to allowit to be compressed against and molded to the delivery device bed. Whenthe gutta percha filler material is adhered to the delivery device bedin this manner, the gutta percha adheres fairly well even without theretentive features. However, the use of the retentive features ispreferred. Further, an adhesive may be used to enhance the connection ofthe filler material 120 to the delivery device bed 118 b′, particularlyat the most terminal/distal end. Adhesive can be used as a retentivefeature by itself, or in combination with any of the other retentivefeatures. If the delivery device is provided with holes 122, the fillermaterial will protrude through the holes 122 as the filler material ismolded to the delivery device bed to form a small button 120 a on theback side of the bed portion, as seen for example in FIGS. 11 and 14A.The button 120 a can have a diameter greater than the diameter of thehole 122, so that the button 120 a overlaps the back surface 119 b ofthe bed 118 b′. If the delivery device is provided with cutouts orindents 124, the filler material, when pressed on to the bed 118 b′,will overlap the back surface of the bed 118 b′ in a similar fashion.This overlapping will facilitate retention of the filler material plug120 on the bed portion 118 b′ of the delivery device 116′ duringpackaging and shipping, for its shelf life, and during positioning ofthe delivery device 116′ (and filler material 120) in a prepared rootcanal. If the delivery device is provided with flanges 125, the fillermaterial 120 will be molded around the flange, such that the flangeextends into the filler material 120.

Although the delivery device 116′ is provided with the filler materialattached in some embodiments, an alternative embodiment may allow forthe delivery device to be provided without the filler material 120attached. In such an embodiment, the practitioner could apply a fillermaterial to the delivery device. For example, in one embodiment, thedelivery device is configured to receive a wide range of fillermaterials selected by a user. Separate coupling devices may be providedto facilitate the coupling of the delivery device and the fillermaterial. Alternatively, the delivery device and/or the filler materialmay be comprised of coupling features to facilitate pairing. In thisinstance, the practitioner can adhere the filler material to the bed ofthe delivery device using adhesives and/or the retentive features notedabove. In addition, the filler material can be softened prior toattachment to the delivery device by heating the filler material orexposing the filler material to solvents (i.e., by dipping the fillermaterial in solvents or brushing solvent on the filler material).

As a variation on the method described above, when using a deliverydevice provided without the filler material, the practitioner can insertthe delivery device into the prepared canal without the plug of fillermaterial. The desired filler material plug can then be inserted into thecanal. In this instance, the shape of the delivery device will act as aguide to facilitate insertion of the plug of filler material into theprepared root canal. When the filler material is inserted into thecanal, the filler material will contact the delivery device at leastalong the bed of the delivery device, so that the delivery device canheat the filler material in situ in the canal, as described above.

In one embodiment of the delivery device, the connecting portion 112′can have a length A of about 10 mm, the stem portion 118 a′ can have alength B of about 18-20 mm, and the bed potion 118 b′ can have a lengthof about 8-10 mm. As discussed herein, the delivery device can beprovided in different sizes, as are, for example, loose gutta-perchaplugs. In this way the bed portions 118 b′ can be of different diametersand tapers. This will accommodate root canals of varying dimensions andtapers. In one embodiment, the taper of the bed portion will correspondto the taper of the file/instrument used to prepare the canal. Canalsalso vary in length. Thus, as discussed herein, the delivery device 116′may be provided with stem portions 118 a′ of various lengths toaccommodate various tooth lengths. The delivery device 116′ (less thefiller plug 120) can be formed in any desired fashion. For example, thedelivery device 116′ can be formed by a stamping, molding, casting,machining, or grinding operation or any other desired manufacturingprocedure. The filler plug 120 will be adhered to the delivery deviceafter the delivery device 116′ is formed. Again, delivery devices can beprovided without the filler material attached.

An embodiment of the holder 114 is shown in FIGS. 17A-E. The holder 114removably receives the connecting portion of the delivery device116,116′. The holder 114 is generally cylindrical in end view (as seenin FIGS. 17B-C), and is generally pen-like in shape in side view (asseen in FIGS. 17A and D). Although shown to be generally straight, theholder 114 could define a bend or angle at its forward end, such thatthe holder is generally contra-angled. However, the holder 114 isrelatively short, for example, being only about 50 mm (about 2″) long.Hence, the holder 114 is only slightly longer than the overall length ofthe delivery device 116, 116′.

In some embodiments, the holder 114 includes a channel 160 which opensat the front of the holder and extends rearwardly from the front of theholder. The channel 160 is sized and shaped to receive the connectingportion of the delivery device 116, 116′. The channel 160 can becontained in an axially movable receptacle 160 a. The receptacle 160 acan completely surround the delivery device connecting portion.Alternatively, the receptacle can define an arc of greater than 180°,and the delivery device connecting portion will snap or click into thereceptacle, or be connected to the receptacle by way of lockingelements, as discussed above.

In some embodiments, the receptacle 160 a can include contacts whichmake electrical connections with the contacts on the connecting portion150 of the delivery device 116, such that the leads 156 a and 157, andhence the heat sensor 156 and heating device (if the heating device isin the shaft bed portion 152 b) will be placed in electricalcommunication with the controller. For both the delivery device 116 and116′, the receptacle electrically connects to the electricallyconductive outer surface of the delivery device, to enable the deliverydevice to operate as the probe of the apex location circuit 186.

In several embodiments, the holder 114 can be provided with a retractiondevice 164 which is operatively connected to the receptacle 160 a tomove the receptacle axially along the channel 160 of the holder. Theretraction device 164 is activated by a controller 166 in the holder.The controller 166 of the holder, in turn, is in communication with themain controller 182 in the base unit 112. The retraction device movesthe receptacle 160 a (and hence the delivery device 116, 116′) axiallyrearwardly along the holder channel from an extended position to aretracted position. The extent of axial movement is at least enough towithdraw the delivery device bed portion from the filler material. Thisretraction process can be programmed to be part of the obturationprocess, in that when all parameters have been met, as discussed herein,the delivery device will be withdrawn from the filler material. Theretraction device can be, for example, a spring, an electric motor, asolenoid, a piston or any other device that can move the receptacle 160a axially within the channel 160. After an obturation cycle iscompleted, the retracting device 164 can be operated to move thereceptacle 160 a back to its extended position for its next use. Thisreturn to the extended position can be automatic, or can happen upon thepressing of a reset button.

In some embodiments, the delivery device 114′ shown in FIG. 18 issubstantially similar to the delivery device 114. However, the deliverydevice 114′ incorporates a plunger 117′. The plunger 117′ is preferablysimilar to the plunger 117 (described below) in that it will have aworking surface which will vary in shape and size as the plunger 117′passes through the canal to mold the filler material. The plunger 117′is operatively connected to a plunger driver 167 which moves the plunger117′ axially. This is shown in FIGS. 29A-C. As shown therein, the system110′ does not include a separate plugger, as does the system of FIG. 7A.Rather, the plugger 117′ is contained within the holder 114′ and extendsthrough the tube-shaped connecting portion of the delivery device 116′to engage the filler material 120 as shown in FIG. 29A. As with theretractor 164, the plunger driver 167 can be any mechanism which canaxially move the plunger relative to the holder. Thus, for example, theplunger driver can be a spring, an electric motor, a solenoid, or apiston. The plunger 117′ is sized and shaped to be able to move axiallythrough the channel 160 and to extend along or through the hollow tubeof the connecting portion 112′ of the delivery device 116′. The plugger117′ is sufficiently long such that the distal end of the plugger canengage, and press against filler material 120. If the system 110 isprovided with the holder 114′, the full obturation cycle can beautomated, and the controller can control the molding of the heatedfiller material using the plugger 117′ and can control the extraction ofthe delivery device 116′, as discussed herein. Hence, all thepractitioner would need to do, in some embodiments, is properly positionthe delivery device 116′ in the root canal and to activate theobturation cycle. The plugger may be disposable or reusable. In thisembodiment, the plugger 117′ can be provided with a pressure transducer.The pressure transducer will generate a signal indicative of the forcebeing applied to the filler material. The pressure signal will bereceived by the controller, and the controller will control the pluggerdriver such that the force applied to the filler material does notexceed a determined about (such as about 7-10 lbs).

An alternative embodiment 114″ of the holder is shown in FIG. 33D. Theholder 114″ is designed for use with the delivery device 116′, andincludes a nose 160′ which is sized to be received in the tube definedby the connecting portion 112′ of the delivery device 116′. Theconnection between the delivery device and the holder nose can be merelya frictional connection. This frictional connection can be enhanced, forexample, by a rubber ring around the connection portion 112′.Alternatively, a mechanism, such as a lock, can be provided for apositive interlocking connection between the delivery device 116′ andthe holder nose 160′. The interlocking connection can be a connectionsuch as discussed above in conjunction with the delivery device 116.That is, the interlocking connection can include a spring biased memberon the delivery device which engages a dimple on the holder nose or apin on the delivery device which engages a bayonet slot on the holdernose. The two portions of the connection can be reversed. That is, thespring biased member can be on the holder nose 160′ and the dimple canbe on the delivery device; similarly, the bayonet slot can be on thedelivery device and the pin can be on the holder nose.

As discussed above, in several embodiments, the heating device can belocated within the holder 114, 114′, 114″. With the connecting portionof the delivery device 116, 116′ being received by the holder receptacle160 a of the holder 114′, the heating device can include, for example,an induction coil that surrounds the chamber 160 to heat the deliverydevice connecting portion and hence the delivery device shaft.Alternatively, a piezo electric element or a rotational magnetic heatingdevice can be provided which generates heat which is delivered to thedelivery device. The heating circuit (which contains the heating device)is in communication with, and controlled, by the control board 166 inthe holder 114 based upon commands from the main controller 182.

The plugger 117, according to some embodiments, is shown generally inFIGS. 19-22. This universal plugger 117 includes, in one embodiment, ahandpiece or handle 212 having a shaft 214 extending from thehandpiece/handle. The shaft 214 is shown in FIG. 19 to be contra-angled,and comprises a working end 216 which engages and molds the fillermaterial. The working end 216 (shown in detail in FIGS. 21 and 22)comprises a stationary plate 218 which is spaced from the distal end 214a of the shaft 214 by means of a post 220. The post 220 extends from thecenter of the distal end 214 a of the shaft 214 and is secured to thestationary plate 218 at the approximate center of the plate 218, as seenin FIG. 20. In an alternative embodiment, this central plate/post cansimply be a post with a shaft and a “stationary plate” of the samediameter. That is, the stationary plate would be defined by the bottomsurface of the post. During an obturation procedure, the post 220 willbe subjected to compression forces. The post 220 is thus made from amaterial (such as a metal, metal alloy, or composite material) whichwill be able to withstand typical compression forces applied to it, suchthat the post 220 will not buckle during a procedure.

In some embodiments, a plurality of moveable plates 222 is providedwhich are moveable independently of each other relative to the post 220and stationary plate 218. Illustratively, each moveable plate 222 isconnected to the working end 216 of the shaft 214 by means of at leastone connector 224. The connector 224 can be a wire, cable, filament orthe like. The connectors 224 are made from a material which will allowthe moveable plates 222 to move horizontally relative to the stationaryplate 218 and the post 220. As illustrated, the movable plates 222 areshown to be behind the stationary plate 218. However, if the centralplate is simply a post, then the moveable plates 222 would be positioneddistal to the central post (not shown). The material from which theconnectors 224 are made will facilitate inward movement upon relativelypassive horizontal forces as well as return of the moveable plate 222 totheir original (expanded) position once the horizontal deflecting forceis removed. In addition, the connectors 224 can resist compressiveforces, such that the distance between the moveable plates 222 and theworking end 216 of the shaft will not be substantially changed when thewires 224 are subject to compressive forces. The connectors 224 can bemade from a metal, metal alloy, composite or plastic material.

In one embodiment, each moveable plate 222 has its own connector 224,such that the moveable plates 222 are individually connected to thedistal end 214 a of the shaft 214. The plates 222 can be moved from anexpanded or open position (shown in FIGS. 21-23) to a closed positionshown in FIG. 25. However, because the plates are movable in two axesindependently of each other, the overall configuration of the plates isnot limited to a generally circular configuration. Stated differently,the moveable plates can move in two degrees of freedom; that is, eachmoveable plate can move along an x-axis and a y-axis relative to thestationary plate. The x-axis for each moveable plate would be defined bya line extending from the center of the stationary plate to bisect themoveable plate; and the y-axis is perpendicular to the x-axis.

As seen in FIG. 24, this freedom of movement allows the plates to attainan overall oval configuration, for example. The ability of each of themoveable plates to move in two axes and independently of each otherenables the moveable plates 222 to define an infinite array of geometricshapes and of different sizes.

Illustratively, in one embodiment, the moveable plates 222 are shown begenerally semicircular, having a curved outer edge and a straight inneredge. The stationary plate 218 is shown to be generally circular. Incombination, the plates 218 and 222 define a plugger or working surface226 (as seen in FIGS. 23-25), in which the moveable plates 222 overlapeach other as well as the stationary plate 218. The movable plates 222can be arranged such that one side of the each moveable plate overliesthe moveable plate, for example to the right, and the other side of themoveable plate is overlaid by the moveable plate to the left. While thisoverlapping arrangement of the moveable plates provides for a smalldegree of slope to each moveable plate 222, the moveable plates 222 aregenerally parallel to each other and to the stationary plate 218. Inuse, the moveable plates 222 are pressed up against each other under anaxial force as the plugger surface is pressed against filler material.The connectors 224 are sufficiently strong to resist this axial force,so that the moveable plates can still move passively in a generallyhorizontal plane relative to each other and the stationary plate 218 asthe movable plates engage the wall of the root canal. Thus, the use ofthe moveable plates provides for the application of axial forces over anarea that is substantially equal to the cross-sectional diameter of thecanal. The axial force applied by the plugger against the fillermaterial to mold the filler material may still allow a small amount offiller material to pass outside of the working or plugging surfaceand/or even between adjacent plates when the molding/packing forces areapplied to the heated filler material. A small amount of filler materialmay escape axial/apical molding in this regard in some cases. However,more effective forces of three-dimensional molding will nonetheless beaccomplished. Several embodiments of the invention are particularlyadvantageous because the working ends are not fixed and allow for theapplication of an axial force over an equivalent area. Hence, use of theplugger 117 will provide for improved obturation results.

The stationary and moveable plates 218 and 222 could be provided inother shapes, as desired. For example, the inner edge of the moveableplates 222 could be curved, rather than straight; the outer edge couldbe polygonal, sinusoidal, or any other desired shape. Alternatively, themoveable plates 222 could be petal or generally tear shaped. The centralstationary plate or post could be polygonal, flower shaped (e.g., astationary area with petals extending from the stationary area), or anyother desired shape. Depending on the size and shape of the moveableplates, the stationary plate 218 and its attendant post 220 could beomitted.

A connector 224 is shown to be secured to each moveable plate 222 alongan outer edge of the moveable plate. However, if desired, the connectionpoint of the connector 224 to the moveable plate 222 can be altered tomost any desired location on the moveable plate. For example, theconnector 224 could be connected at the approximate center of themoveable plate 222 or the connector 224 could be connected to themoveable plate along its inner edge. The connector 224 is shown to begenerally in the shape of an elongated or stretched “S”. However, theconfiguration or shape of the connector 224 could be changed to be anydesired shape. For example, the connector 224 could be straight, ratherthan generally S-shaped. In this instance, the connector 224 woulddefine a slope. The degree of the slope would be defined by theconnection point of the connector 224 to the plate 22. Alternatively,the connector could be

-shaped or arced (e.g., curved with a generally constant radius).

The connector 224, like the post 218, will be subjected to compressionforces during an obturation procedure. Hence, the connector 224 must bemade from a material which will be sufficiently strong to resist thecompression forces (e.g., avoid buckling under typical compactionpressures) yet allow for horizontal translation of the plates relativeto each other and the stationary plate 218. That is, the connector willhave a shape and length such that the movable plates 222 have a normalposition in the open position (FIG. 23). During obturation, as will bedescribed below, the position of the moveable plates 222 relative toeach other and to the stationary plate 218 will change (for example, tothe orientations shown in FIG. 24 or 25). When the plugger is withdrawnfrom the root canal, the connectors 224 will return the plates to thenormal open position of FIG. 23. As will be apparent, the shape of theconnector, as discussed above, may affect the ability of the wire towithstand the compression forces.

Typical loads applied by a practitioner to the plugger's working end canbe in the range of 30,000 lbs/in², whereas the corresponding pressuresread at the filler material—root interface upon typically warmgutta-percha compaction techniques are about 2,333 lbs/in². Saiddifferently, forces generated during typical warm gutta-percha packingprocedures are about 4.2 lbs. That is, practitioners have been shown toapply about 4.2 lbs. of load when molding/packing the filler materialwhich, in turn causes about 2,333 lbs/in² of pressure to the rootsurface. This level of force has been shown to safe as a prepared rootcanal has been shown to be able to safely withstand 2500 lbs/in²However, if the load to the root canal wall exceeds the 2500 lbs/in²range, root fracturing becomes a concern. As stated above, lateralforces to root canal walls generated by currently available pluggerseasily exceed this threshold if inadvertently locked into the canal.According to several embodiments of the invention, the plugger (e.g.,plugger 117) will decrease this type of locking to the canal asdiscussed below; however, compaction of the filler material will stillgenerate lateral forces on the root surface. The knowledge of theseparameters can influence the tolerances of the materials used toconstruct the plugger 117. As an example, so that the post 220 andconnectors 224 will not buckle under proper loads, the post 220 andconnectors 224 can withstand loads of at least 4.2 lbs. In addition, thepost 220 and connectors 224 could be allowed to buckle if the loadapplied to the plugger exceeds 4.2 lbs. Buckling of the post andconnectors at loads in excess of 4.2 lbs would help prevent transmissionof excess lateral forces to the root canal wall (through molding/packingof the filler material), in an effort to help prevent fracturing of theroot canal wall.

Additionally, in several embodiments, the connection of the post 220 andthe connectors 224 to the stationary plate 218 and the moveable plates222, respectively, are able to withstand the forces to which they willbe subject during an obturation procedure, thereby minimizing the riskof the stationary plate 218 or the moveable plates 222 separating fromthe post 220 or connectors 224, respectively. In addition, theindividual plates can be retained in lateral orientation. To this end,as seen in FIG. 20, the distal end 214 a of the shaft 214 is providedwith circumferential, axially extending holes 228 which receive one endof the connectors 224. Hence, the connectors 224 are embedded in thedistal end 214 a of the shaft 214. Similarly, the post 220 is embeddedat the distal end 214 a of the shaft 214 in the approximate center ofthe shaft distal end 214 a. Although not shown, the plates 218 and 222can be provided with receptacles which receive the opposite ends of thepost 220 or connectors 224.

In some embodiments, the connectors 224 position the moveable plates 222so that the moveable plates 222 are vertically close in proximity to thestationary plate 218. The moveable plates 222 are shown to be slightlyvertically above the stationary plate 218, however, they could beconfigured to be slightly vertically below the stationary plate 218. Inoperation, as noted above, the stationary plate 218 in combination withthe individual moveable plates 222 define the plugger surface 226 whichengages the filler material to mold/pack the filler material into theroot canal to fill and seal the root canal. Further, as illustrativelyshown, the moveable plates 222 overlap each other, such that there areno axially visible gaps between the plates (e.g., such that the plates,in combination, define an uninterrupted surface in plan view, as seen inFIGS. 23-25). If desired, the moveable plates 222 can be positionedrelative to each other and/or the stationary plate 118 such thathorizontal gaps are formed between the plates, such as shown in theplugger surface 226′ of FIG. 28. As noted above, despite the fact thatsome heated filler material may pass between adjacent plates as theplugger surface exerts axial forces on the heated filler material,because the plugger surface 226 has an area that approximates thecross-sectional area of the root canal at substantially all levels ofthe root canal during which the plugger surface is in contact with thefiller material, use of the plugger 117 will provide better filling andsealing than currently available pluggers.

In an embodiment for sealing the apex of a root canal, the diameter ofthe distal end 214 a of the shaft 214 has a diameter D of about 0.5 mm.The size and number of moveable plates 222 enables the plugger surface226 to define an approximate circle in the open position (as in FIG. 23)that is about 1.0 mm in diameter, and to define a circle in the closedposition (as in FIG. 25) of slightly greater than 0.5 mm. It isanticipated that the plugger will be provided in different sizes (e.g.,small, medium and large), so that different pluggers can be used fordifferent teeth or different purposes. For example, the illustratedplugger can be a small plugger which could be used to seal the apex of aroot canal or to mold/pack filler material in a tooth with a narrow rootcanal. A medium plugger may have a shaft with a diameter of 0.8 mm and alarge plugger could have a shaft with a diameter of 2.0 mm. The oval,shown in FIG. 24, can have a minor axis as small as the diameter of thestationary plate 218 (which has a diameter that can be less than thediameter D of the shaft distal end 214 a), and a major axis that canexceed the illustrative 1.0 mm diameter of the generally circularplugger surface 226 of FIG. 23. As can be appreciated, the variation insize of the plugger surface 226 can attain will be dependent on the sizeand shape of the stationary plate 218 and the moveable plates 222.Additionally, the complexity of the circumference of the plugger surface226 that can be attained will be determined by the number and shape ofthe moveable plates 222. In the illustrative figures, the plugger 117includes five movable plates. This enables the plugger surface 226 toattain the generally circular or generally oval shapes shown in FIGS.23-25. However, if additional moveable plates were provided, the pluggersurface could attain move complex shapes. For example, the pluggersurface could attain a generally hour-glass configuration. As notedabove, the use of movable plates 222 which are movable relative to eachother and to the stationary plate 218 allow the plugger surface 226 toachieve an infinite number of shapes to enable the plugger surface togenerally approximate and generally conform to the cross-sectionalsize/shape of the root canal at virtually any level in the root canal.The complexity of the shapes that can be obtained and the ability forthe plugger surface to approximate the cross-sectional shape of the rootcanal at a specific level in the root canal increases as the number ofmoveable plates increases and as the size of the moveable platesdecrease. Although the moveable plates 222 are all shown to be generallythe same size and shape, the moveable plates of a plugger could beprovided in two or more shapes and sizes. This variation in size andshape of the moveable plates on a plugger may even further enhance theability of the plugger surface to conform generally to thecross-sectional shape of the root canal.

In an obturation procedure, after the filler material (plug) has beenfitted, sized and properly positioned in the root canal, thepractitioner will insert the plugger 117 into the root canal tomold/pack the filler material plug. As the plugger 117 is inserted intothe canal, the outer edge of the moveable plates 222 will engage thewall of the root canal, causing the moveable plates 222 to move relativeto each other, such that the shape of the plugger surface 226 will bealtered to conform generally to the cross-sectional shape of the rootcanal. The shape or configuration of the plugger surface 226 may bealtered to define a smaller circle, or the configuration of the pluggersurface 226 may be altered to be more oval than circular. In oneembodiment, the moveable plates 226 provide for a plugger which definesa plugging surface 226 which will vary in shape throughout the length ofthe root canal such that the plugging surface 226 will approximate thecross-sectional shape and size of the canal at all levels of the rootcanal, such that substantially the full upper surface of the fillermaterial plug will be covered by the plugger surface 226. In severalembodiments, the plugger will be able to decrease in size as it movesdown a tapered canal preparation. This will substantially reduce theamount of, or even prevent, the filler material from moving axiallyaround the plugger 117 and toward the tooth crown, as occurs withcurrently available pluggers, as the plugger presses into and exerts anaxial force on the filler material. In one embodiment, the fillermaterial will not be forced toward the tooth crown as the plugger isurged into the warmed filler material. Stated differently, rather thanbeing displaced upwardly, the warmed gutta-percha will be forced to moveapically (toward the apex of the canal). By substantially preventing thefiller material from moving toward the tooth crown, it will facilitate abetter molding/packing of the filler material to thereby better mold thefiller material to the full anatomy of the root canal. That is, thefiller material will be better molded to fill lateral canals, fistulas,ledges, etc. of the root canal. This will ultimately create a betterseal of the root canal.

In one embodiment, by enabling the shape of the plugger surface 226 tovary, and to vary instantaneously as the plugger passes through thecanal to mold the filler material, the plugger 117 can adapt to theinfinite number of potential cross-sectional shapes of the canal thatmay be present. While there may nonetheless be some gaps between theedge of the plugger surface 226 and the root canal wall, there will begreater surface area contact of the plugger surface 226 with the fillermaterial than occurs with currently available fixed diameter pluggers.As can be appreciated, as the number of moveable plates 222 increasesand the size of the plates decrease, the ability of the plugger surface226 to more accurately conform to, or approximate, the cross-sectionalshape of the root canal at any particular level in the root canal willimprove. This will allow for greater molding/packing forces. Hence, theplugger 117 will facilitate a better filling of the root canal systemwith the filler material. Further, it is noted that because the moveableplates 222 are moved by contact with the root canal wall, the lateralforces applied by the plugger to the root canal wall will be minimal.Additionally, in one embodiment, by enabling the shape of the pluggersurface 226 to vary automatically in response to the cross-sectionalshape of the root canal wall, the practitioner may only need to use asingle plugger for a complete obturation procedure. Stated differently,the practitioner will not need to use multiple fixed-diameter pluggers,as is currently required, to perform an obturation of a root canal.

In accordance with another aspect of the plugger 117, a button 230 (FIG.19) can be provided on the plugger handle 212 proximate the forward endof the handle 212. The button 230 is operatively connected to moveableplates 222, such that when the button 230 is pressed, the moveableplates 222 will be drawn in to reduce the area or size of the pluggersurface 226. This will allow for general maneuvering of the pluggerwithin the root canal. For example, the plugger 117 can be provided witha loop that surrounds the connectors 224 proximate the distal end 214 aof the shaft 214. This loop could reside in an annular channel at distalend of the shaft 214 and which surrounds the connectors 224. A controlwire will extend through the shaft 214, to operatively connect thebutton to the loop. When the button is pressed, it will effectively pullthe control wire to reduce the effective size of the loop. Reduction ofthe size of the loop will cause the loop to constrict around theconnectors 224 within the shaft 214 a, thereby pulling the moveableplates 222 inwardly to reduce the size of the plugger surface 226. Inanother embodiment, a distal chamber (not shown) can be formed at theworking end 214 a of the shaft 214. This chamber would internallycontain what is illustrated in FIG. 20, and the connectors 224 andmoveable plates 222 as well as the central post 220 and the stationaryplate 218 would be operatively connected to button 230 through thischamber so that when the button 230 is pressed the chamber (again notshown) can be pulled back into the working end's outer tube 214 a. Thiswould also cause the circumferential size/shape of the working end todecrease.

In accordance with another embodiment, the plugger can be provided witha heat sensor 240 (FIG. 26), such as a thermocouple, which isillustratively shown to be on the stationary plate 218. The heat sensor240 is operably connected to a display 242 in the handle 212 via a wire244 which passes through the post 220 and shaft 214. The display 242 canbe controlled by a microchip (not shown) which can be incorporated aspart of the display and which will receive a temperature signal from theheat sensor 240. Based on the signal from the sensor, the temperature ofthe filler will be shown on the plugger display 242. Thus, with theplugger surface 226 in contact with the filler material, the temperatureof the filling material (at least at the upper end of the fillermaterial) will be shown on the display 242. Although the display 242 isshown to be on the handpiece 212 in FIG. 19, the temperature sensorcould be place in communication with the control on the system base unitor the delivery device holder such that the temperature will be shown onthe displays on the base unit and/or the holder. If the display isremote from the handpiece, the connection between the plugger and thedisplay can be wireless or corded.

In one embodiment, display of temperature of the filler (either on theplugger hand piece 212, base unit or the holder) will provide thepractitioner with needed information regarding the temperature of thefiller material (e.g., plug) while it is being molded. Gutta-percha,when heated above a certain temperature (i.e., above about 42° C.-49°C.), typically changes between a beta phase and an alpha phase. As thegutta-percha in the alpha phase cools, the gutta-percha shrinksslightly. If molding pressure is removed from the gutta-percha plug tooearly (i.e., before shrinking ends), gaps may form between the moldedgutta-percha plug and the wall of the root canal. However, by being ableto monitor the temperature of the gutta-percha plug, the practitionercan maintain a molding/packing pressure on the gutta-percha plug untilpotential shrinkage of the gutta-percha has stopped. This willsubstantially reduce the likelihood that gaps will form between themolded gutta-percha plug and the root canal wall because of shrinkage,thus providing for a better seal of the root canal. If the temperatureinformation is transmitted to a control system, the control system cancontrol the heating of the filler material to precisely maintain thefiller material at a desired temperature (e.g., below the temperaturemediated phase transitions of the filler material). Additionally, thecontrol system can use the temperature information to control anautomatic obturation procedure also described above.

In accordance with another embodiment, the plugger can be provided witha pressure transducer which monitors the force applied to the fillermaterial. This pressure transducer could be in communication with acontroller to provide a warning (either auditory, visual, or tactile) ifthe desired pressure is exceeded). Such a pressure transducer can belocated on one of the plates or at a junction between the plates andtheir respective posts/connectors or at the junction of thepost/connectors with the shaft 214. The applied pressure could also beshown on the plugger display 242, on the base unit display or on aholder display.

FIG. 27 shows a plugger 117″ having a “standard” plugger shaft 214″.That is, the plugger shaft is not provided with a working end 216 as isthe plugger 117. Rather the working end of the shaft 214″ is of constantdiameter. However, the plugger 117″ is shown with a heat sensor 240 anddisplay 242. The plugger 214″ could also be provided with the notedpressure transducer. Thus, although the plugger 117″ lacks the benefitsof the variable shaped plugging surface 226 or 226′, the plugger 117″will still display the temperature of the filler material, and thusfacilitate the practitioner applying a molding pressure to the fillermaterial until the temperature falls below a desired temperature. Also,this type of plugger could be utilized to regulate embodiments of theobturation method described herein. As previously described, precisetemperature delivery can be controlled by having the temperature sensorin close proximity to the filler material at the time of heat delivery.

Modifications can be made to the plugger as shown and described. Forexample, rather than being connected to the shaft 214 a, the moveableplates 222 could be connected to the stationary plate 218. For example,each moveable plate could move along a path in the stationary platedefined by a slot. This would, however, allow the moveable plates tomove in one axis rather than in two axes. Further, although the moveablyplates are shown to fully surround the stationary plate, the stationaryplate could only be partially surrounded by the moveable plates.Additionally, depending on the shape of the moveable plates, thestationary plate could be omitted. In this instance, the inner area ofthe movable plates would combine to replace and fill in the area wherethe stationary plate was located.

In another embodiment of this universal plugger, the plugger could beprovided with a vibrational generator which is adapted to inducevibrations (such as sonic or ultrasonic vibrations) in the plates.Inducing vibrations would potentially enhance molding of the fillermaterial in the root canal. The generator can be a sonic or ultrasonicvibration generator. Other types of generators to generate vibrationsforces can be used as well.

Turning to FIG. 30, the control system 180 of the system 110, 110′includes the main controller 182, an apex locating circuit 186, aheating circuit 184, the temperature sensor 156, and a timer 188. Themain controller 182 is housed in the base unit 112, along with the baseunit display 130 and the input buttons. The apex locating circuit 186,the heating circuit 184, the plugger driver 167, the retraction device162, and the holder display are all on the holder and are incommunication with the holder controller 166. In addition, a pressuretransducer 187, if provided on the plugger, is in communication with theholder controller 166, such that the holder controller receives thepressure signal from the pressure transducer 187. Any of the retractiondevice 162, the plugger driver 167 and the holder display can be omittedfrom the holder, and hence from the system. Additionally, as notedabove, the heat sensor can be located on or near the plugger workingend, on the delivery device, or any other part of the system that willallow for an accurate determination of the temperature of the apicalfiller material or other desired site (e.g., tissue). The maincontroller 182 is in communication with the apex locating circuit 186,the heating circuit 184, the temperature sensor 156, and the pressuretransducer 187 by way of the holder controller 166, and the timer 188.In the system 110 (FIG. 7A) where the plugger 117 is separate from theholder, the plugger is placed in communication with the base unit, andhence, the signal from the pressure transducer 187 would be receiveddirectly by the main controller 182, rather than by the holdercontroller 166.

In one embodiment, as with the system control system of FIG. 5, the maincontroller 182 receives signals indicative of the location of thedelivery device (and hence the filler material) from the apex locatingcircuit 186, signals indicative of the temperature of the fillermaterial from the temperature sensor 156, and signals indicative of thepressure exerted by the plugger from the pressure transducer 187. Thecontroller 182 uses this information, as well as the information fromthe timer, to drive the display 130 (to display the filler temperatureand the location of the filler plug/cone in the canal), and to controlthe heating circuit 184. In addition, if the holder 114 is provided witha delivery device retraction mechanism 162 and/or a plugger driver 167,the controller 182 uses the signals from the timer 186, the heat sensor156, and the pressure transducer 187 to control the delivery deviceretraction mechanism and/or the plugger driver. The buttons 132 on thebase unit 112 define an input device which is in communication with themain controller 182 to enable the practitioner to adjust the settemperature for the heating circuit and the heating cycle duration.Additionally, the base unit 112 can include a sound generator (notshown), as noted above, to provide sound signals to inform thepractitioner of certain information, such as that the delivery device isin an acceptable location to begin heating, that the delivery device isextending through the apical foramen of the root canal, that theappropriate temperature has been reached and/maintained for the pre-settime, that the delivery device should be withdrawn from the tooth,and/or that the heating process should be inactivated.

In one embodiment, the apex locating circuit 186 includes the deliverydevice 116, 116′ (which forms the probe of the circuit), the lip clip148, and a resistance monitor 66 (as shown in FIG. 6A). The apexlocating circuit produces an output which is received by the base unitcontroller 182 or the holder controller 166 (if the lip clip isconnected directly to the holder). In the latter instance, the holdercontroller 166 transmits location information to the main controller182.

In one embodiment, the heating circuit 184 includes the heating devicewhich can be located either on the delivery device 116, 116′ or on theholder 114, 114′, 114″.

As noted above, the optional temperature sensor(s) can be located eithernear the working end of the plugger, on the delivery device bed portion,or any other part of the system that will allow for an accuratedetermination of the temperature of the apical filler material, or otherdesired site. If the temperature sensor is located on the plugger, thetemperature sensor information, in one embodiment, can be transmittedinitially to the holder controller 166 (if the plugger is directlyconnected to the holder) or to the main controller 182 (if the pluggeris directly connected to the base unit). If the control of the system180 is centralized in the base unit, the controller 182 receives thetemperature information (either directly from the temperature sensor oras transmitted by the holder controller 166) and controls the heatingcircuit 184 (and hence the heating device) in response to thetemperature sensor output. The main controller 182 also drives thedisplay 130 in response to the output from the temperature sensor tovisibly show the temperature of the filler material in the canal.

In one embodiment, the heating circuit 184 is additionally controlled inresponse to the output from the apex locating circuit 186 and the timer188. As noted above, the heating circuit 184 will not be activatedunless the controller (holder controller 166 or main controller 182)determines that the end of the delivery device 116,116′ (and hence theend of the filler material) is within a determined distance of theapical foramen of root canal. Further, the heating circuit will not beactivated if the delivery device is extending through the apical foramenof the root canal. The timer 188 is activated once the control systemdetermines that filler material 154 has been directly heated at itsdeepest level to the desired set temperature (between about, 37° C.-65°C., e.g., about 39° C.-47° C. or about 42° C.-45° C.). If the holderincludes the plugger driver, the controller 182, in one embodiment, willsend a signal to the holder controller 166 to activate the pluggerdriver to exert a molding pressure or load on the filler material. Ifthe plugger 117 includes the temperature sensor, then, in oneembodiment, the plugger surface will have been in contact with thefiller material from the moment the obturation cycle is started. Whenthe timer 188 has determined that the predetermined temperature has beenachieved and held for the set time period (about 2-10 seconds), thecontroller 182 or controller 166 will deactivate the heating circuit184. If the holder includes the retraction device 162, in oneembodiment, the controller 182 will send a signal to the holdercontroller 166 to activate the retraction device to withdraw thedelivery device 116, 116′ from root canal just prior to the controller182 sending the signal to deactivating the heating circuit 184. If thesystem is not provided with an automatic retraction device 162, theholder display and/or the main controller display 130 will prompted thepractitioner to manually remove the delivery device just before theheating circuit is deactivated. Such a prompt can be a tactile, visualor audio prompt. Lastly, if the holder is provided with the pluggerdriver, in one embodiment, the system can maintain the molding force onthe filler until the filler material drops to a predetermined value(such as about 37° C., i.e., normal body temperature). At that point,the plugger can be retracted by the plugger driver. The plugger driverwill be controlled in response to the output from the pressuretransducer, so that a predetermined force (i.e., not more than about 7lbs) will not be exceeded as the plugger is urged against the fillermaterial to mold the filler material. If the temperature sensor is onthe plugger, then the plugger driver can be activated to retract theplugger in response to the temperature signal. However, it thetemperature sensor is located on the delivery device, activation of theplugger driver to retract the plugger may be based on an average timefor the filler material to cool from the set temperature to the desired“cool” temperature, such as around body temperature. The above method isshown in flow chart form in FIG. 34.

The procedure is also shown with respect to a tooth in FIGS. 33A-K. InFIG. 33A, a prepared tooth is presented. In FIG. 33B-C, the deliverydevice with the filler material 120 is inserted into the canal. TheX-ray of FIG. 31 shows the delivery device 116′ positioned in the rootcanal. In FIG. 33D, of the nose 160′ of the delivery device 114″ isinserted into the connector portion 112′ of the delivery device toconnect the delivery device to the holder. Although the drawings of FIG.33 show the holder 114″, the holder 14, 114, or 114′ could be used aswell. In one embodiment, the delivery device could be mounted to theholder for the insertion of the delivery device into the root canal.With the delivery device connected to the holder, the delivery devicewill be connected into the apex locating circuit and will be in heattransfer communication with the heating device. In FIG. 33E, the plugger117 is inserted into the root canal. Here, the plugger 117 is separatefrom the holder and delivery device. If the holder 114′ (which has theinternal plugger 117′) is used, then the plugger will descend from theholder, as shown in FIGS. 29A-C. In FIG. 33F, the system has confirmedthat the delivery device is in a proper location in the root canal, andhas activated the heating circuit to heat the filler material. Becausethe delivery device shaft extends along the side of the filler material,the delivery device shaft will not interfere with the placement and useof the plugger while the delivery device is in place in the root canal.Hence, the obturation system allows for the practitioner to mold thefiller material while the filler material is being heated and during theheating cycle. This is shown for example, in the x-ray images of FIGS.31A and 32 and in FIG. 33G. In FIG. 31A, a temperature sensor, in theform of a thermocouple, can be seen at the end of the plugger.

FIG. 29A is one example of how an automated system may look as the topof the delivery device connects into a heating chamber, and the plugger(with the thermocouple at its working end) slides down the center. Thesystem can be programmed to be automated in this embodiment: Forexample, clicking the delivery device into the holder channel completesthe apex locating circuit to confirm location, the plugger allows forthe feedback from the heating element to establish and control thetemperature delivered to the filler material, and for feedback from thepressure transducer to control the plugger driver. The plugger can holdand mold the filler material, and the heating chamber can be programmedto remove the delivery device when all parameters have been established.

The molding pressure is continued through FIGS. 33H-J to mold the fillermaterial to the root canal system. As can be seen, by comparing FIGS.33H, I and J, the upper end of the filler material lowers from FIGS.39H-J, and the lateral canals fill with filler material as the fillermaterial is molded to 3-dimensionally seal the root canal. In FIG. 33J,the heating time has elapsed, and the delivery device is being withdrawnfrom the root canal. Once the delivery device is withdrawn from thecanal, the source of heat (i.e., the delivery device) for the fillermaterial will have been removed from the canal, and the heating circuitwill be deactivated. As seen, in one embodiment, in FIG. 33K the pluggerremains in the canal to continue to exert its molding pressure on thefiller material to continue molding of the heated filler material, andto prevent the withdrawal of the delivery device from the canal fromaffecting the positioning of the filler material in the canal. Finally,in FIG. 33K, molding pressure is retained on the filler material as thefiller material cools to reduce the possibility of voids or gaps formingbetween the filler material and the root canal wall as the fillermaterial cools. A completed obturation is shown in the x-ray of FIG.31C. As seen, the filler material 120 has been pressed or molded intothe root canal so that the filler material fills and seals lateralcanals which are visible.

In several embodiments, use of the delivery device 116, 116′ will besubstantially similar to the use of the delivery device 16, and need notbe redescribed.

The obturation system, according to several embodiments, has one or moreof the following advantages. First, the systems 10, 110, and 110′deliver heat directly to the filler material and along the entirelength, or substantially along the length, of the filler material at aprecise temperature, and are not limited to delivering heat only to thetop of the filler material. As discussed above, applying heat from thetop of the filler material does not allow for much heat to reach theapex of the filler material, as conventional filler materials (such asgutta-percha) are not good conductors of heat. Gutta-percha can onlytransmit heat well from about 1 mm, after which its heat conductioncapacity drops sharply, and the gutta-percha cannot reliably transferheat more than 2-4 mm. Thus, in some embodiments, the delivery deviceextends to the distal tip of the gutta-percha, or up to about 2 mm fromthe distal tip. In other embodiments, the delivery device extends morethan 2 mm from distal tip (e.g., for use with filler materials thatallow better conductivity). Another advantage of several embodiments ofthe system is the small temperature gradient from the top to bottom ofthe filler material. Yet another advantage of several embodiments of thesystem is the reduced temperature needed. Because heat is appliedlaterally (from the side) rather than only longitudinally (from the top)of the filler material, the temperatures that are delivered the fillermaterial do not need to be as high as 200-300° C. Such temperatures arewell in excess of the temperature mediated phase transitions ofgutta-percha, and are even far in excess of the molding temperature ofthe gutta-percha that is needed to seal a root canal. Further, inseveral embodiments, the system 10, 110, 110′ and especially the systems110 and 110′ of FIGS. 7A-12 and 29A-C, allows for packing and molding ofthe filler material during the heating cycle, rather than after theheating cycle.

Additionally, several embodiments of the system utilize apex locatingtechnology at the time of obturation or sealing. Currently existing apexlocating devices are used before final seating of the filler material inthe canal, rather than at final seating of the filler material in thecanal. Thus, although the practitioner can be fairly certain that theroot canal has been prepared to the apical foramen of the root canal,without a device such as the obturation system 10, 110, or 110′, thepractitioner is less certain that the filler material is properlypositioned in the canal at this stage of the obturation procedure.

Additionally, by controlling the temperature of the filler material andnot heating gutta-percha filler material beyond the temperature mediatedphase transitions according to some embodiments, shrinkage can beavoided or minimized, and the physical and mechanical properties of thefiller material are able to be controlled and utilized.

As various changes could be made in the constructions herein withoutdeparting from the scope of the claimed invention, it is intended thatall matter contained in the description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense. For example, although the systems 10, 110, and 110′ are shown toinclude controllers in their respective holders 14, 114, and 114′ theholder controllers could be omitted, and the system could rely on asingle controller in the base unit. In this instance, appropriatesignals to and from the various components would travel through thecords connecting the holder, plugger and lip clip to the base unit. Theholder 14 is described as being used with the delivery device 16; andthe holder 114 is described as being used with the delivery device 116,116′. However, any of the disclosed holders 14, 114, 114′, 114″ could beadapted to be receive any of the disclosed delivery devices 16,116,116′.

In an alternate construction, the heating device can be contained withina chamber mounted on the plugger 117. In this variation, the deliverydevice 16, 116, 116′ could connect or snap into to a retractable chamberon the plugger, and the plugger effectively becomes the holder. Thisretractable chamber could function as the heating chamber describedherein. This connection of the delivery device to the retractableheating chamber would allow for the completion of the circuitrydiscussed herein. This includes the ability to confirm the correctposition of the delivery device by analyzing the impedance and/orresistance in the apex locating circuit. If deemed in the correctposition, this connection would then allow for direct heat transfer downthe delivery device substantially along the entire length of the fillermaterial. The working end of the plugger (which can contain athermocouple) could be in contact with the filler material and feedbackto the retractable heating chamber to confirm and regulate theestablishment of the desired temperature for molding. Simultaneously asthe heat is being delivered directly to the entire length of the fillermaterial, three-dimensional compaction can occur. In addition, duringthis time of ideal molding conditions, the retractable chamber can beactivated to remove the delivery device while the plugger secures andfurther molds the filler material. Once the plugger senses that thefiller material has reached body temperature the plugger, containing thedelivery device (minus the filler material) can be withdrawn and removedfrom the chamber mounted on the plugger for the next use.

The technology discussed herein was designed to enhance the sealing ofroot canal systems through a precise heat delivery and regulatedthree-dimensional molding/compaction. However, it is intended that thesetreatment modalities will carry over to other fields of use,particularly in medicine and the life sciences. Thus, althoughembodiments described herein are useful for obturation, they may also beused for other dental applications as well. In addition, non-dentalmedical applications are also well-suited for several embodiments. Forexample, the delivery device and plugger may be used to deliver, orfacilitate insertion of, a variety of filler materials, including butnot limited to, moldable biocompatible medical grade fillers into thebody (such as bone cement for orthopedic applications, hydrogels,natural and synthetic grafts, etc.). The plugger, in some embodiments,is used to facilitate controlled insertion and stabilization ofbiomedical implants (such as stents, screws, and other temporary orpermanent implants). In one embodiment, the distal end of the plunger isbiocompatible and detachable and can, for example, serve as a barrier toextrusion for an implanted device. The use of pluggers described hereinthat are capable of adjusting to closely conform to changing diameterswill be beneficial in several other applications. For example, this willallow for increased compaction forces when placing materials inarthroscopic surgery, such as the placement of stents through randomlychanging ducts, arteries, veins, etc. In addition, precise heat andpressure measurements with related feedback systems will have benefit inthis, as well as other treatment modalities. As a further example,measuring temperature and pressure within the tube/systems that drainblood in traumatic brain injuries, or other neurovascular orcardiovascular conditions, will aid in accuracy and precision.

The description herein illustrates various embodiments by way of exampleand not by way of claimed limitation. The non-limiting terms“embodiment” and “aspect” are used interchangeably. Additionally, it isto be understood that the claims are not limited in its application tothe details of construction and the arrangements of components set forthin the following description or illustrated in the drawings. The claimedinvention(s) is capable of other embodiments and of being practiced orbeing carried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

What is claimed is:
 1. An obturation system for facilitating filling ofa root canal system, comprising: a delivery device comprising a shafthaving a bed portion at a distal end thereof; said bed portion having aninner surface and an outer surface, said inner surface defining a fillermaterial receiving surface; said bed portion being generally arcuate inshape and wherein said inner surface is concave and said outer surfaceis convex; and a biocompatible filler material comprising an uppersurface, a side surface, and a distal end; said biocompatible fillermaterial being mounted to said filler material receiving surface of saidbed portion; and wherein said outer surface of said bed portion issubstantially free of biocompatible filler material; wherein thedelivery device bed portion has a greater thermal conductivity than thefiller material; and wherein said filler material receiving surface ofthe bed portion of the shaft wraps at least partially around the sidesurface of the filler material and contacts the outer surface of thefiller material substantially along an entire length of the fillermaterial such that a distal end of the bed portion is at, or proximate,the distal end of the filler material.
 2. The system of claim 1, whereinthe filler material comprises gutta-percha.
 3. The system of claim 1,wherein said bed portion is in heat transfer communication with saidfiller material; said system further comprising a heating device, saidheating device being in thermal communication with said bed portion;whereby said bed portion delivers heat laterally into said fillermaterial from said outer surface of said filler material to heat thefiller material substantially uniformly and substantially the fulllength of the filler material.
 4. The system of claim 3 wherein saidheating device comprises a heating element positioned at said bed. 5.The system of claim 3 wherein said shaft and bed portion are made from amaterial that is, at least in part, heat conductive; said heating devicecomprising said heat conductive material.
 6. The system of claim 3,further comprising a temperature sensor, and a controller, wherein thetemperature sensor is positionable to be in heat sensing contact withthe filler material in the root canal; said temperature sensortransmitting a temperature signal indicative of the temperature of thefiller material; and wherein the controller is configured to be incommunication with said temperature sensor to receive the temperaturesignal from said temperature sensor; wherein the controller is furtherconfigured to be in communication with said heating device to controlsaid heating device, and thus the heating of the filler material, inresponse to the signal from said temperature sensor.
 7. The system ofclaim 6, wherein said temperature sensor is located on said deliverydevice.
 8. The system of claim 3, further comprising a holder adapted toremovably receive said delivery device; said holder comprising saidheating device.
 9. The system of claim 8, wherein said holder comprisesan axially movable retractor to which said delivery device is removablyconnectable; said retractor being operable to retract said deliverydevice from an extended position to a retracted position; said retractorbeing adapted to move said delivery device axially within said rootcanal a distance sufficient to withdraw the delivery device from saidfiller material.
 10. The system of claim 8, wherein a controller is inoperative communication with said retractor; said controller emitting acommand to automatically activate said retractor after said fillermaterial has been heated to a predetermined temperature for apredetermined period of time.
 11. The system of claim 1 furtherincluding a controller; said controller being in communication with aheating device to control said heating device to deliver heat to thefiller material to substantially thoroughly and substantially uniformlyheat the filler material to a temperature at which the filler materialis moldable yet which is below the melting point of said fillermaterial.
 12. The system of claim 1, including a connecting portion at aproximal end of said shaft; said connecting portion being adapted toconnect said delivery device to a holder.
 13. The system of claim 12,wherein said connecting portion comprises a lock for removably securingthe delivery device to a holder.
 14. The system of claim 13, whereinsaid lock comprises (1) one of a bayonet slot which receives a pin or apin which is received in a bayonet slot or (2) one of a spring biasedmember and a groove which receives a spring biased member.
 15. Thesystem of claim 12, wherein said connecting portion comprises a hollowtube, said tube being opened at upper and lower ends thereof.
 16. Thesystem of claim 1 wherein said shaft is generally arcuate incross-section along a plane generally perpendicular to an axis of saidshaft.
 17. An obturation system for facilitating filling of a root canalsystem, comprising: a delivery device; said delivery device comprising ashaft having a bed portion at a distal end thereof; said bed portionbeing generally arcuate in shape and having an inner concave surface, anouter convex surface and side edges extending between the inner andouter surfaces; said inner concave surface defining a filler materialreceiving surface; a biocompatible filler material comprising an uppersurface, a tapered side surface and a distal end; said biocompatiblefiller material being mounted to said filler material receiving surfaceof said bed portion along said outer surface of said filler materialsuch that said filler material receiving surface of said bed portion isin intimate contact with said side surface of said filler material andwherein said outer surface of said bed portion is substantially free ofbiocompatible filler material; wherein the delivery device bed portionhas a greater thermal conductivity than the filler material, and aheating device in thermal communication with said bed portion; whereby,when said heating device is activated, said bed portion is heated andheat is transferred laterally from said bed portion to said fillermaterial; and wherein the bed portion of the shaft extends along anouter surface of the filler material and contacts the filler materialfrom the upper surface of the filler material to a point between thedistal end of the filler material and about 2 mm from the distal end ofthe filler material to facilitate heat transfer to the distal end of thefiller material.
 18. The system of claim 17, wherein the filler materialcomprises a cone-shaped plug of gutta-percha and the delivery device iscomprised of or is coated at least in part with platinum, silver, gold,copper, or aluminum or alloys thereof.
 19. The delivery device of claim17, wherein the delivery device is made from an electrically conductivematerial or has an electrically conductive coating on an outer surfaceof said device.
 20. The delivery device of claim 17, wherein thedelivery device is made from a heat conductive material.
 21. Thedelivery device of claim 17, wherein said heating device comprises aheating element located at said bed portion.
 22. The obturation systemof claim 17 wherein said heat delivery device heats said filler materialsuch that the temperature difference along any two points on the fillermaterial does not exceed more than 20° C. when said filler material isheated.
 23. The obturation system of claim 17 wherein the bed portion ofthe shaft extends along an outer surface of the filler material andcontacts the filler material from the upper surface of the fillermaterial to a point substantially proximate the distal end of the fillermaterial.